Category: Class 10

Students can download 10th Science Chapter 18 Heredity Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 18 Heredity

Samacheer Kalvi 10th Science Heredity Text Book Back Questions and Answers

I. Choose the correct answer.

Question 1.
According to Mendel alleles have the following character:
(a) Pair of genes
(b) Responsible for character
(c) Production of gametes
(d) Recessive factors
Answer:
(b) Responsible for character

Question 2.
9 : 3 : 3 : 1 ratio is due to ______.
(a) Segregation
(b) Crossing over
(c) Independent assortment
(d) Recessiveness.
Answer:
(c) Independent assortment

Question 3.
The region of the chromosome where the spindle fibres get attached during cell division:
(a) Chromomere
(b) Centrosome
(c) Centromere
(d) Chromonema
Answer:
(c) Centromere

Question 4.
The centromere is found at the centre of the ______ chromosome.
(a) Telocentric
(b) Metacentric
(c) Sub – metacentric
(d) Acrocentric.
Answer:
(b) Metacentric

Question 5.
The units form the backbone of the DNA.
(a) 5 carbon sugar
(b) Phosphate
(c) Nitrogenous bases
(d) Sugar phosphate
Answer:
(d) Sugar phosphate

Question 6.
Okazaki fragments are joined together by ______.
(a) Helicase
(b) DNA polymerase
(c) RNA primer
(d) DNA ligase.
Answer:
(d) DNA ligase.

Question 7.
The number of chromosomes found in human beings are:
(a) 22 pairs of autosomes and 1 pair of allosomes.
(b) 22 autosomes and 1 allosome
(c) 46 autosomes
(d) 46 pairs autosomes and 1 pair of allosomes.
Answer:
(a) 22 pairs of autosomes and 1 pair of allosomes.

Question 8.
The loss of one or more chromosome in ploidy is called ______.
(a) Tetraploidy
(b) Aneuploidy
(c) Euploidy
(d) Polyploidy.
Answer:
(b) Aneuploidy

II. Fill in the blanks:

1. The pairs of contrasting character (traits) of Mendel are called ……..
2. Physical expression of a gene is called ………..
3. The thin thread like structures found in the nucleus of each cell are called ……….
4. DNA consists of two ……….. chains.
5. An inheritable change in the amount or the structure of a gene or a chromosome is called ……….

Answer:

1. alleles or allelomorphs
2. Phenotype
3. Chromosomes
4. Polynucleotide chain
5. Mutation

III. Identify whether the statement are True or False. Correct the false statement.

1. A typical Mendelian dihybrid ratio of F₂ generation is 3 : 1.
2. A recessive factor is altered by the presence of a dominant factor.
3. Each gamete has only one allele of a gene.
4. Hybrid is an offspring from a cross between genetically different parent.
5. Some of the chromosomes have an elongated knob-like appendages known as telomere.
6. New nucleotides are added and new complementary strand of DNA is formed with the help of enzyme DNA polymerase.
7. Down’s syndrome is the genetic condition with 45 chromosomes.

Answer:

1. False – A typical Mendelian dihybrid ratio of F₂ generation is 9 : 3 : 3 : 1
2. True
3. True
4. True
5. False – Some of the chromosomes have an elongated knob-like appendages known as satellite
6. True
7. True

IV. Match the following:

Answer:
A. (iii)
B. (iv)
C. (v)
D. (i)
E. (ii)

V. Answer in a sentence.

Question 1.
What is a cross in which inheritance of two pairs of contrasting characters are studied?
Answer:
Dihybrid cross is a cross in which inheritance of two pairs of contrasting characters.

Question 2.
Name the conditions when both the aisles are identical?
Answer:
Homozygous alleles.

Question 3.
A garden pea plant produces axial white flowers. Another of the same species produced terminal violet flowers. Identify the dominant trait.
Answer:
The dominant trait is axial white flower.

Question 4.
What is the name given to the segments of DNA, which are responsible for the inheritance of a particular character?
Answer:
Genes are the segments of DNA, which are responsible for the inheritance of a particular character.

Question 5.
Name the bond which binds the nucleotides in a DNA.
Answer:
Hydrogen bond binds the nucleotides in a DNA.

VI. Short Answer Questions.

Question 1.
Why did Mendel select pea plant for his experiments?
Answer:

1. It is naturally self-pollinating and so is very easy to raise pure breeding individuals.
2. It has a short life span as it is an annual and so it was possible to follow several generations.
3. It is easy to cross-pollinate.
4. It has deeply defined contrasting characters.
5. The flowers are bisexual.

Question 2.
What do you understand by the term phenotype and genotype?
Answer:

• The external expression of a particular trait is known as the phenotype.
• The genetic expression of an organism is a genotype.

Question 3.
What are allosomes?
Answer:
Allosomes are chromosomes which are responsible for determining the sex of an individual. They are also called as sex chromosomes or hetero-chromosomes. There are two types of sex chromosomes, X and Y- chromosomes.

Question 4.
What are the Okazaki fragments?
Answer:
The short segments of DNA are called Okazaki fragments.

Question 5.
Why is euploidy considered to be advantageous to both plants and animals?
Answer:
Euploidy is the condition in which individual bears more than the usual number of diploid (2n) chromosome. It is used in plant breeding and horticulture. It has economic significance by the production of large sized flowers and fruits. It plays a significant role in the evolution of new species.

Question 6.
A pure tall plant (TT) is crossed with the pure dwarf plant (tt), what would be the F₁ and F₂ generations? Explain.
Answer:
In the F₁ generation, all are tall plants. (Genotype all are Tt and phenotype all are tall).
In F₂ generation, genotype three tall and one dwarf. [TT : Tt : tt = 1 : 2 : 1] phenotype.
Tall : dwarf 3 : 1 [TT : Tt : Tt : tt].

Question 7.
Explain the structure of a chromosome.
Answer:
The chromosomes are thin, long and thread like structures consisting of two identical strands called sister chromatids. They are held together by the centromere. Each chromatid is made up of spirally coiled thin structure called chromonema. The chromonema has number of bead-like structures along its length which are called chromomeres.

Question 8.
Label the parts of the DNA in the diagram given below. Explain the structure briefly.
Answer:
(i) DNA molecule consists of two polynucleotide chains.
(ii) These chains form a double helix structure with two strands which run anti-parallel to one another.
(iii) Nitrogenous bases in the centre are linked to sugar-phosphate units which form the backbone of the DNA.
(iv) Pairing between the nitrogenous bases is very specific and is always between purine and pyrimidine linked by hydrogen bonds.

VII. Long Answer Questions

Question 1.
Explain with an example of the inheritance of dihybrid cross. How is it different from a monohybrid cross?
Answer:
Dihybrid cross involves the inheritance of two pairs of contrasting characteristics (or contrasting traits) at the same time. The two pairs of contrasting characteristics chosen by Mendel were shape and color of seeds: round-yellow seeds and wrinkled-green seeds.
Mendel crossed pea plants having round-yellow seeds with pea plants having wrinkled-green seeds. Mendel made the following observations:

(i) Mendel first crossed pure breeding pea plants having round-yellow seeds with pure breeding pea plants having wrinkled-green seeds and found that only round-yellow seeds were produced in the first generation (F₁). No wrinkled-green seeds were obtained in the F₁ generation. From this it was concluded that round shape and yellow color of the seeds were dominant traits over the wrinkled shape and green color of the seeds.

(ii) When the hybrids of F₁ generation pea plants having round-yellow seeds were cross-bred by self pollination, then four types of seeds having different combinations of shape and color were obtained in second generation or F₂ generation. They were round yellow, round-green, wrinkled-yellow and wrinkled-green seeds.
The ratio of each phenotype (or appearance)of seeds in the F₂ generation is 9 : 3 : 3 : 1. This is known as the Dihybrid ratio.

Monohybrid cross is a genetic cross that involves a single pair of gene or trait. In this parents differ by single trait. Eg: Height.
Dihybrid cross is a genetic cross that involves two pairs of genes, which are responsible for two trait. In this, parents have two different independent trait. Eg: flower colour, stem length.

Question 2.
How is the structure of DNA organised? What is the biological significance of DNA?
Answer:
DNA is the genetic material of almost all the organisms. One of the active functions of DNA is to make its copies which are transmitted to the daughter cells. Replication is the process by which DNA makes exact copies of itself. Replication is the basis of like and takes place during the inter phase stage.

During replication of DNA, two complementary strand of DNA unwind and separate from one end in a zipper like fashion. The enzyme helicase unwinds the two strands of the DNA. The enzyme called topoisomerase separates the double helix above the replication fork and removes the twists formed during the unwinding process. For the synthesis of new DNA, two things are required. One is RNA primer and enzyme primase. The DNA polymerase moves along the newly formed RNA primer nucleotides, which leads to the elongation of DNA. In the other strand DNA is synthesized in small fragments called Okazaki fragments.

These fragments are linked by the enzyme called ligase. In the resulting DNA, one of the strand is parental and the other is the newer strands which is formed discontinuously.

Significance of DNA:
(i) It is responsible for the transmission of hereditary information from one generation to next generation.
(ii) It contains information required for the formation of proteins.
(iii) It controls the developmental process and life activities of an organism.

Question 3.
The sex of the new born child is a matter of chance and neither of the parents may be considered responsible for it. What would be the possible fusion of gametes to determine the sex of the child?
Answer:
Sex determination is a chance of probability as to which category of sperm fuses with the egg. If the egg (X) is fused by the X-bearing sperm an XX individual (female) is produced. If the egg (X) is fused by the Y-bearing sperm an XY individual (male) is produced. The sperm, produced by the father, determines the sex of the child. The mother is not responsible in determining the sex of the child.

Now let’s see how the chromosomes take part in this formation. Fertilization of the egg (22+X) with a sperm (22+X) will produce a female child (44+XX). while fertilization of the egg (22+X) with a sperm (22+Y) will give rise to a male child (44+XY).

VIII. Higher Order Thinking Skills: (HOTS)

Question 1.
Flowers of the garden pea are bisexual and self-pollinated. Therefore, it is difficult to perform hybridization experiment by crossing a particular pistil with the specific pollen grains. How Mendel made it possible in his monohybrid and dihybrid crosses?
Answer:
He worked on nearly 10,000 pea plants of 34 different varieties. He had chosen 7 pairs of contrasting characters. As the pea plants, are self-pollinating it is easy to raise pure breeding individuals. It is easy to cross-pollinate. It has contrasting characters. So Mendel made it possible in his monohybrid and dihybrid crosses.

Question 2.
Pure-bred tall pea plants are first crossed with pure-bred dwarf pea plants. The pea plants obtained in F₁ generation are then cross-bred to produce F₂ generation of pea plants.
(a) What do the plants of F₁ generation look like?
(b) What is the ratio of tall plants to dwarf plants in F₂ generation?
(c) Which type of plants were missing in F₁ generation but reappeared in F₂ generation?
Answer:
(a) plants will be tall
(b) 3 : 1
(c) Tall heterozygous (Tt)

Question 3.
Kavitha gave birth to a female baby. Her family members say that she can give birth to only female babies because of her family history. Is the statement given by her family members true? Justify your answer.
Answer:
The statement given by her family members were not true. It is not hereditary or family history. The sex determination mainly depends on which category of sperm fuses with the egg. If the egg [X] is fused by the X – bearing sperm, an XX individual (female) is produced. If the egg [X] is fused by the Y – bearing sperm an XY individual (male) is produced.

IX. Value-Based Questions

Question 1.
Under which conditions does the law of independent assortment hold good and why?
Answer:
During meiosis, chromosomes assort randomly into gametes, such that the segregation of alleles of one gene is independent of alleles of another gene. This is stated in Mendel’s Second Law and is known as the law of independent assortment.

Samacheer Kalvi 10th Science Heredity Additional Important Questions and Answers

I. Choose the correct answer.

Question 1.
Exchange of genetic material take place in:
(a) vegetative reproduction
(b) asexual reproduction
(c) sexual reproduction
(d) budding
Answer:
(c) sexual reproduction

Question 2.
In human, the number of chromosomes in each cell is _______
(a) 22 pairs
(b) 21 pairs
(c) 23 pairs
(d) 20 pairs
Answer:
(c) 23 pairs

Question 3.
If a round green seeded pea plant (RRYY) is crossed with wrinkled, yellow seeded pea plant,(rrYY) the seeds produced in F₁ generation are:
(a) round and yellow
(b) round and green
(c) wrinkled and green
(d) wrinkled and yellow
Answer:
(a) round and yellow

Question 4.

In the new complementary strand of DNA, in one strand, the daughter strand is synthesized, as a continuous strand called ______
(a) Lagging strand
(b) Parent strand
(c) RNA primer
(d) Leading strand
Answer:
(d) Leading strand

Question 5.
A zygote which has an X-chromosome inherited from the father will develop into a:
(a) boy
(b) girl
(c) x- chromosome does not determine the sex of a child
(d) either boy or girl
Answer:
(b) girl

Question 6.
In pea, a pure tall plant (TT) is crossed to a short plant (tt). The ratio of pure tall plants to short plants in F2 is:
(a) 1 : 3
(b) 3 : 1
(c) 1 : 1
(d) 2 : 1
Answer:
(b) 3 : 1

Question 7.
The number of pairs of sex chromosomes in the zygote of human is:
(a) one
(b) two
(c) three
(d) four
Answer:
(a) one

Question 8.
Pure breeding varieties are otherwise called as:
(a) dominant
(b) recessive
(c) wild type
(d) mixed type
Answer:
(c) wild type

Question 9.
The genotype of a character is influenced by factors called:
(a) chromosome
(b) nucleus
(c) cytoplasm
(d) genes
Answer:
(d) genes

Question 10.
Monosomy is represented by:
(a) 2n + 1
(b) 2n – 1
(c) 2n + 2
(d) 2n – 2
Answer:
(b) 2n – 1

Question 11.
The term chromosome was introduced by:
(a) Bridges
(b) Waldeyer
(c) Balboni
(d) Flemming
Answer:
(b) Waldeyer

Question 12.
Diagrammatic representation of Karyotype of a species is:
(a) Idiogram
(b) Albinism
(c) Karyo tyning
(d) Heredity
Answer:
(a) Idiogram

II. Fill in the blanks:

1. The Genotypic ratio of Monohybrid cross is ………….
2. ……… is a graphical representation to calculate the probability of all possible genotype of off spring in a genetic cross.
3. The gene is present at a specific position on the chromosome called ……….
4. The end of the chromosome is called ………
5. The chromosomes with satellites are called as ………..
6. ……… act as a aging clock in every cell.
7. Nitrogen base + sugar = …………
8. The two strands of DNA open and separate at the point forming …………
9. Nullisomy is represented by ……….
10. The gametes produced by the organisms contain a single set of chromosomes is ……….
Answer:
1. 1 : 2 : 1
2. Punnet square
3. Locus
4. Telomere
5. Sat-chromosome
6. Telomeres
7. Nucleoside
8. Replication fork
9. 2n – 2
10. haploid (n)

III. Match the following:

Answer:
A. (v)
B. (i)
C. (ii)
D. (iii)
E. (iv)

IV. State whether True or false, If false write the correct statement:

1. The daughter strand synthesized in DNA is called logging strand.
2. The centromere is found near the centre of the chromosome in sub metacentric.
3. Primary construction in chromosome is called as nucleolar organizer.
4. T.H. Morgan was awarded Nobel prize for determining the role of chromosome in heredity.
5. Adenine links Thymine with three hydrogen bonds.

Answer:

1. False – The daughter strand synthesized in DNA is called leading strand
2. True
3. False – Primary construction in chromosome is called as secondary construction.
4. True
5. False – Adenine links Thymine with two hydrogen bonds.

V. Answer in a word or sentence:

Question 1.
What is heredity?
Answer:
Heredity is transmission of characters from one generation to the next generation.

Question 2.
What is Alleles or Allelomorphs?
Answer:
The factors making up a pair of contrasting characters are called alleles or allelomorphs.

Question 3.
Define variation.
Answer:
Differences shown by the individuals of the same species and also by the offspring of the same parents.

Question 4.
What is Terminus?
Answer:
The replication fork of DNA, of the two sides, meet at a site called terminus.

Question 5.
Write the expanded form of DNA.
Answer:
Deoxyribo nucleic acid

Question 6.
What is the satellite?
Answer:
Some of the chromosomes have an elongated knob-like appendage at one end of the chromosome known as the satellite.

Question 7.
How many types of nitrogenous bases are present in DNA? Name them.
Answer:
There are two types of nitrogenous bases in DNA. They are purines (Adenine and Guanine) pyrimidines (Cytosine and Thymine).

Question 8.
Why is DNA called polynucleotide?
Answer:
DNA is a large molecule consisting of millions of nucleotides. Hence it is called as polynucleotide.

Question 9.
Name two purine nitrogenous bases found in a DNA molecule.
Answer:
Adenine and Guanine

Question 10.
What are the three chemically essential parts of nucleotides containing a DNA?
Answer:
Nitrogenous base, pentose sugar and phosphate.

Question 11.
What are autosomes?
Answer:
Autosomes are chromosomes that contain genes which determine the somatic characters.

Question 12.
How is the sex of a new born determines in humans?
Answer:
The sperm produced by the father determines the sex of the child.

Question 13.
Define genetics.
Answer:
The branch of biology that deals with the genes genetic variation and heredity of living organisms is called genetics.

Question 14.
Define mutation.
Answer:
Mutation is an inheritable sudden change in the genetic material (DNA) of an organism.

Question 15.
Name the types of chromosomes based on the position of centromere.
Answer:
Based on the position of centromere, the chromosomes are classified as Telocentric, Aerocentric, submeta centric and meta centric.

VI. Short Answer Questions

Question 1.
What are chromosomes made up of?
Answer:
Chromosomes are made up of DNA, RNA, chromosomal proteins (histones and non-histones) and certain metallic ions. These proteins provide structural support to the chromosome.

Question 2.
What is the mechanism behind the expression of a particular trait? Explain.
Answer:
The factor for each character or trait remain independent and maintain their identity in the gametes. The factors are independent to each other and pass to the offspring through gametes.

Question 3.
If a pure tall pea plant is crossed with a pure dwarf plant, then in the first generation only tall plant appears.
(a) What happens to the traits of the dwarf plant?
(b) In the second generation, the dwarf trait reappears? Why?
Answer:
(a) The tall plant (dominant) mask the expression of the dwarf plant.
(b) When F₁ hybrids are self crossed, the two entities separate and then unite independently forming tall and dwarf plant.

Question 4.
Explain the types of chromosome-based on function.
Answer:
Based on function, the chromosomes are classified into:

1. Autosomes: Autosomes contain genes that determine the somatic (body) characters. Male and female have an equal number of autosomes.
2. Allosomes: Allosomes are responsible for determining the sex of an individual. They are also called sex chromosomes or heterochromosomes. There are two types of sex chromosomes.

The human male has one X chromosome and one Y chromosome and human female have two X chromosomes.

VII. Long Question and Answer:

Question 1.
How are Mutation classified? Explain.
Answer:
Mutations are classified into two main types, namely chromosomal mutation and gene mutation.
Chromosomal mutation:
The sudden change in the structure or number of chromosomes is called a chromosomal mutation. This may result in
(i) Changes in the structure of chromosomes: Structural changes in the chromosomes usually occurs due to errors in cell division. Changes in the number and arrangement of genes take place as a result of deletion, duplication, inversion and translocation in chromosomes.

(ii) Changes in the number of chromosomes: They involve addition or deletion in the number of chromosomes present in a cell. This is called ploidy. There are two types of ploidy
(a) Euploidy (b) Aneuploidy.

Gene or point mutation: Gene mutation is the changes occurring in the nucleotide sequence of a gene. It involves substitution, deletion, insertion or inversion of a single or more than one nitrogenous base. Gene alteration results in abnormal protein formation in an organism.

Question 2.
What is a mutation? Explain the two types of mutation.
Answer:
The mutation is an inheritable sudden change in the genetic material (DNA) of an organism. Mutations are broadly classified into 1. Chromosomal mutation and 2. Gene mutation.

1. Chromosomal Mutation:
The sudden change in the structure or number of chromosomes is called chromosomal mutation. This result in
(a) Change in the structure of chromosomes: Structural changes occur due to errors in cell division. Changes in the number and arrangement of genes take place as a result of deletion, duplication, inversion and translocation in chromosomes.

(b) Changes in the number of chromosomes: They involve addition or deletion in the number of chromosomes present in a cell and is called ploidy. The two types of ploidy are:

(i) Euploidy: It is the condition, in which the individual bears more than the usual number. If an individual has three haploid sets of chromosomes, the condition is called triploidy [3n]. Triploid plants and animals are sterile. If an individual has four haploid sets of chromosomes, the condition is called tetraploidy [4n], Tetraploid plants often result in increased fruit and flower size.

(ii) Aneuploidy:
It is the loss or gain of one or more chromosomes in a set. It is of three types:

• Monosomy [2n – 1]
• Trisomy [2n + 1]
• Nullisomy [2n – 2]

(iii) Down’s syndrome:
It is one of the commonly known aneuploid condition, in man. It is a genetic condition, in which there is an extra copy of chromosome 21 (Trisomy 21). It is associated with mental retardation, delayed development, behavioural problems, weak muscle tone, vision and hearing disability are some of the conditions seen in children.

2. Gene or point mutation:
Gene mutation is the changes occurring in the nucleotide sequence of a gene. It involves substitution, deletion, insertion or inversion of a single or more than one nitrogenous base. Gene alteration results in abnormal protein formation.

Question 3.
Write a note on down’s syndrome.
Answer:
Down’s syndrome: This condition was first identified by a doctor named Langdon Down in 1866. It is a genetic condition in which there is an extra copy of chromosome 21 (Trisomy 21). It is associated with mental retardation, delayed development, behavioural problems, weak muscle tone, vision and hearing disability are some of the conditions seen in these children.

VIII. Higher Order Thinking Skills: (HOTS)

Question 1.
In a plant gene ‘A’ is responsible for tallness and its recessibe allele ‘a’ for dwarfness and ‘B’ is responsible for red colour to recessive allele ‘b’ for white flower colour. A tall and red flowered plant with genotype AaBb crossed with dwarf and red flowers (aaBb). What is the percentage of dwarf white flowered off spring of above cross?
Answer:
12.5 %

Question 2.
In a population of 1000 individuals 360 belong to genotype AA, 480 to Aa and the remaining 160 to aa. Based on this data, the frequency of allele A in the population is:
Answer:
0.6

Question 3.
A tall true breeding garden pea plant is crossed with dwarf true breeding garden Pea plant. When the F₁ plants were selfed the resulting genotypes were in the ratio of:
Answer:
1 : 2 : 1 :: Tall homozygous; Tall heterozygous Dwarf.

Students can download 10th Science Chapter 16 Plant and Animal Hormones Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 16 Plant and Animal Hormones

Samacheer Kalvi 10th Science Plant and Animal Hormones Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
Gibberellins cause:
(a) Shortening of genetically tall plants
(b) Elongation of dwarf plants
(c) Promotion of rooting
(d) Yellowing of young leaves
Answer:
(b) Elongation of dwarf plants

Question 2.
The hormone which has a positive effect on apical dominance is _____.
(a) Cytokinin
(b) Auxin
(c) Gibberellin
(d) Ethylene.
Answer:
(b) Auxin

Question 3.
Which one of the following hormones is naturally not found in plants:
(a) 2, 4-D
(b) GA3
(c) Gibberellin
(d) IAA
Answer:
(a) 2, 4-D

Question 4.
Avena coleoptile test was conducted by _____.
(a) Darwin
(b) N. Smit
(c) Paal
(d) F.W. Went.
Answer:
(d) F.W. Went.

Question 5.
To increase the sugar production in sugarcanes they are sprayed with
(a) Auxin
(b) Cytokinin
(c) Gibberellins
(d) Ethylene
Answer:
(d) Ethylene

Question 6.
LH is secreted by _____.
(a) Adrenal gland
(b) Thyroid gland
(c) Anterior pituitary
(d) Hypothalamus.
Answer:
(c) Anterior pituitary

Question 7.
Identify the exocrine gland:
(a) Pituitary gland
(b) Adrenal gland
(c) Salivary gland
(d) Thyroid gland
Answer:
(c) Salivary gland

Question 8.
Which organ acts as both exocrine gland as well as endocrine gland?
(a) Pancreas
(b) Kidney
(c) Liver
(d) Lungs.
Answer:
(a) Pancreas

Question 9.
Which one is referred to as “Master Gland”?
(a) Pineal gland
(b) Pituitary gland
(c) Thyroid gland
(d) Adrenal gland
Answer:
(b) Pituitary gland

II. Fill in the blanks:

1. ………. causes cell elongation, apical dominance and prevents abscission.
2. …………. is a gaseous hormone involved in abscission of organs and acceleration of fruit ripening.
3. ……… causes stomatal closure.
4. Gibberellins induce stem elongation in ……… plants.
5. The hormone which has negative effect on apical dominance is ………
6. Calcium metabolism of the body is controlled by ………
7. In the islets of Langerhans, beta cells secrete ………
8. The growth and functions of thyroid gland is controlled by ………..
9. Decreased secretion of thyroid hormones in the children leads to ………

Answer:

1. Auxin
2. Ethylene
3. Abscisic acid
4. Rosette
5. Ethylene
6. Parathormone
7. Insulin
8. Thyroid Stimulating Hormone (TSH)
9. Cretinism

III. Match Column I with Columns II and III

Question 1

Answer:

Question 2.
Match the following hormones with their deficiency states.

Answer:
A. (iii)
B. (v)
C. (ii)
D. (i)
E. (iv)

IV. State whether True or false, If false write the correct statement.

1. A plant hormone concerned with stimulation of cell division and promotion of nutrient mobilization is cytokinin.
2. Gibberellins cause parthenocarpy in tomato.
3. Ethylene retards senescence of leaves,flowers and fruits.
4. Exopthalmic goiter is due to the over secretion of thyroxine.
5. Pituitary gland is divided into four lobes.
6. Oestrogen is secreted by corpus luteum.

Answer:

1. True
2. True
3. False – Ascorbic Acid retards senescence of leaves, flowers and fruits.
4. True
5. False – Parathyroid gland is divided into four lobes.
6. False – Oestrogen is produced by the Graffian follicles.

V. Assertion and Reasoning:

Direction: In each of the following questions a statement of assertion (A) is given and a corresponding statement of reason (R) is given just below it. Mark the correct statement as.
Question 1.
Assertion (A): Application of cytokinin to marketed vegetables can keep them fresh for several days.
Reason (R): Cytokinins delay senescence of leaves and other organs by mobilisation of nutrients.
(a) If both A and R are true and R is correct explanation of A
(b) If both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) Both A and R are false
Answer:
(b) If both A and R are true but R is not the correct explanation of A

Question 2.
Assertion (A): Pituitary gland is referred as “Master gland”.
Reason (R): It controls the functioning of other endocrine glands.
(a) If both A and R are true and R is correct explanation of A
(b) If both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) Both A and R are false
Answer:
(a) If both A and R are true and R is correct explanation of A

Question 3.
Assertion (A): Diabetes mellitus increases the blood sugar levels.
Reason (R): Insulin decreases the blood sugar levels.
(a) If both A and R are true and R is correct explanation of A
(b) If both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) Both A and R are false
Answer:
(a) If both A and R are true and R is correct explanation of A

VI. Answer in a word or sentence:

Question 1.
Which hormone promotes the production of male flowers in Cucurbits?
Answer:
Gibberellin promotes the production of male flower in Cucurbits.

Question 2.
Write the name of synthetic auxin.
Answer:
2, 4 D (2, 4 Dichlorophenoxy Acetic acid).

Question 3.
Which hormone induces parthenocarpy in tomatoes?
Answer:
Gibberellin induces parthenocarpy in tomatoes.

Question 4.
What is the hormone responsible for the secretion of milk in the female after childbirth?
Answer:
Prolactin stimulates the production of milk after childbirth. Oxytocin helps milk ejection from the mammary gland after childbirth.

Question 5.
Name the hormones which regulates water and mineral metabolism in man.
Answer:
Mineralocorticoids hormones of Adrenal cortea maintain the water balance and mineral metabolism in man.

Question 6.
Which hormone is secreted during an emergency situation in a man?
Answer:
The hormones of Adrenal medulla,

• Epinephrine (Adrenaline)
• Norepinephrine (Noradrenaline) are secreted during an emergency situation in man.

Question 7.
Which gland secretes digestive enzymes and hormones?
Answer:
Pancreas secretes digestive enzymes and hormones.

Question 8.
Name the endocrine glands associated with kidneys.
Answer:
Adrenal gland, which is called suprarenal glands is associated with kidneys.

VII. Short Answer Questions:

Question 1.
What are synthetic auxins? Give examples.
Answer:
Artificially synthesized auxin which has the properties of auxins are called Synthetic Auxin. Eg: 2, 4-D

Question 2.
What is bolting? How can it be induced artificially?
Answer:
Treatment of rosette plants with gibberellin induces sudden shoot elongation followed by flowering is called bolting. It can be induced artificially before the crop is harvested.

Question 3.
Bring out any two physiological activities of abscisic acid.
Answer:
The two physiological activities of abscisic acid are:

1. During water stress and drought conditions, Abscisic acid causes stomatal closure.
2. Abscisic acid induces bud dormancy towards the approach of winter in trees like birch.

Question 4.
What will you do to prevent leaf fall and fruit drop in plants? Support your answer with reason.
Answer:

• Very chill deposition on leaves and fruits cause the drop in plants. Protect the tree from frost providing an overhead cover.
• The plant hormone ethylene controls fruit ripening, flower wilting and leaf fall by stimulating the conversion of starch and acids to sugar.

Question 5.
What are chemical messengers?
Answer:
Endocrine glands control and coordinate the body functions through secreting certain chemical messengers called hormones.

Question 6.
Write the differences between endocrine and exocrine gland.
Answer:

Question 7.
What is the role of parathormone?
Answer:
The parathormone regulates calcium and phosphorus metabolism in the body. They act on bone, kidney and intestine to maintain blood calcium levels.

Question 8.
What are the hormones secreted by posterior lobe of the pituitary gland? Mention the tissues on which they exert their effect.
Answer:
The hormones secreted by the posterior pituitary are:

1. Vasopressin or Antidiuretic hormone: In kidney tubules it increases reabsorption of water.
2. Oxytocin: They exert their effect on the muscles of uterus which helps in the contraction of smooth muscles of uterus at the time of child birth and milk ejection from mammary gland after child birth.

Question 9.
Why are thyroid hormones referred to as personality hormone?
Answer:
Thyroid hormones are referred to as personality hormone because they are essential for normal physical, mental and personality development.

Question 10.
Which hormone requires iodine for its formation? What will happen if intake of iodine in our diet is low?
Answer:
The formation of Thyroxine or Thyroid hormone requires iodine. If there is an inadequate supply of iodine in our diet it leads to goitre.

VIII. Long Answer Questions:

Question 1.
(a) Name the gaseous plant hormone. Describe its three different actions in plants.
(b) Which hormone is known as a stress hormone in plants? Why?
Answer:
(a) Ethylene is a gaseous plant hormone. It is a growth inhibitor. The different actions of ethylene are as follows:

• Ethylene promotes the ripening of fruits, eg. Tomato, Apple, Mango, Banana and etc.
• Ethylene inhibits the elongation of stem and root in dicots.
• Ethylene hastens the senescence of leaves and flowers.
• Ethylene stimulates the formation of Abscission zone in leaves, flowers and fruits. This leads to premature shedding.
• Ethylene breaks the dormancy of buds, seeds and storage organs.

(b) Abscisic acid (ABA) is a growth inhibitor which regulates abscission and dormancy. It increases the tolerance of plants to various kinds of stress. So, it is also called a stress hormone.

Question 2.
Describe an experiment which demonstrates that growth stimulating hormone is produced at the tip of coleoptile.
Answer:
Frits Warmolt Went (1903 – 1990), a Dutch biologist demonstrated the , existence and effect of auxin in plants. He did a series of experiments in , Avena coleoptiles.

In his first experiment he removed the tips of Avena coleoptiles. The cut tips did not grow indicating that the tips produced something essential for growth.In his second experiment he placed the agar blocks on the decapitated coleoptile tips. The coleoptile tips did not show any response. In his next experiment he placed the detached coleoptile tips on agar blocks. After an hour, he discarded the tips and placed this agar block on the decapitated coleoptile. It grew straight up indicating that some chemical had diffused from the cut coleoptile tips into the agar block which stimulated the growth.

From his experiments went concluded that a chemical diffusing from the tip of coleoptiles was responsible for growth and he named it as “Auxin” meaning “to grow”.

Question 3.
Write the physiological effects of gibberellins.
Answer:

• Application of gibberellins on plants stimulates extraordinary elongation of internodes. eg. Com and Pea.
• Treatment of rosette plants with gibberellin induces sudden shoot elongation followed by flowering, called bolting.
• Gibberellins promote the production of male flowers in monoecious plants like Cucurbits
• Gibberellins break the dormancy of potato tubers.
• Gibberellins is inducing the formation of seedless fruit, termed as Parthenocarpic fruits (Development of fruits without fertilization) eg. Tomato.

Question 4.
Where are oestrogens produced? What is the role of oestrogens in the human body?
Answer:
Oestrogen is produced by the Graafian follicles of the ovary.
Functions of oestrogens:

1. It brings about the changes that occur during puberty.
2. It initiates the process of oogenesis.
3. It stimulates the maturation of ovarian follicles in the ovaiy.
4. It promotes the development of secondary sexual characters (breast development, high pitched voice etc).

Question 5.
What are the conditions which occur due to lack of ADH and insulin? How are the conditions different from one another?
Answer:
Lack of ADH: Deficiency of ADH (Antidiuretic hormone) reduces the reabsorption of water and causes an increase in urine output (polyuria). This deficiency disorder is called Diabetes insipidus.
Lack of insulin: The deficiency of insulin causes Diabetes mellitus. It is characterised by,

• Increase in blood sugar level (Hyperglycemia).
• Excretion of excess glucose in the urine (Glycosuria).
• Frequent Urination (Polyuria).
• Increased thirst (Polydipsia).
• Increase in appetite (Polyphagia).

Lack of ADH reduces the reabsorption of water and increases the urine output. Lack of insulin causes the Diabetes mellitus, which increases the blood sugar level and excrete the excess glucose in the urine, causing frequent urination.

Insulin:
Deficiency in insulin causes Diabetes mellitus.
Insulin deficiency increase the blood sugar level (Hyperglycemia), excretion of excess glucose in the urine (Glycosuria), frequent urination (Polyuria) increased thirst (Polydipsia), increase in appetite (Polyphagia).

IX. Higher Order Thinking Skills: (HOTS)

Question 1.
What would be expected to happen if
(a) Gibberellin is applied to rice seedlings.
Answer:
Causes imemodal elongation in rice.

(b) A rotten fruit gets mixed with unripe fruits.
Answer:
If a rotten fruits get mixed with unripe fruit. Then the ethylene produced from the rotten fruit will hasten the ripening of the unripe fruits.

(c) When cytokinin is not added to culture medium.
Answer:
Formation of new organs from the callus in tissue culture (Morphogenesis) will not be formed.

Question 2.
A plant hormone was first discovered in Japan when rice plants were suffering from Bakanae disease caused by Gibberella fujikoroi. Based on this information answer the following questions:

1. Identify the hormone involved in this process.
2. Which property of this hormone causes the disease?
3. Give two functions of this hormone.

Answer:

1. Gibberellins
2. Intermodal elongation
3. Functions:
   • promotes the production of male flowers in monoecious plants.
   • Gibberellins break the dormancy of potato tubers.

Question 3.
Senthil has high blood pressure, protruded eyeball and increased body temperature. Name the endocrine gland involved and hormone secretion responsible for this condition.
Answer:
The gland involved is the thyroid gland. The hormone involved in a thyroid hormone. It is due to excess secretion of thyroid hormones called hyperthyroidism which leads to Graver’s disease.

Question 4.
Sanjay is sitting in the exam hall. Before the start of the exam, he sweats a lot, with an increased rate of heartbeat. Why does this condition occur?
Answer:
This is due to the secretion of the hormone Adrenaline in Adrenal medulla of Adrenal gland.

Question 5.
Susan’s father feels very tired and frequently urinates. After clinical diagnosis he was advised to take an injection daily to maintain his blood glucose level. What would be the possible cause for this? Suggest preventive measures.
Answer:
A balance between insulin and glucogon production is necessary to maintain blood glucose concentration.
The deficiency of insulin causes Diabetes Mellitus.
Preventive measure:

1. Take proper or balanced diet.
2. Exercise regularly
3. Avoid stress.

Samacheer Kalvi 10th Science Plant and Animal Hormones Additional Important Questions and Answers

I. Choose the correct answer

Question 1.
Auxin is mainly produced by:
(a) Apical root meristem
(b) Root cambium
(c) Apical shoot meristem
(d) Phloem in shoot tip
Answer:
(c) Apical shoot meristem

Question 2.
Plant hormones are;
(a) Growth regulators
(b) Growth promoters
(c) Growth inhibitors
(d) None of the above
Answer:
(a) Growth regulators

Question 3.
Pick out the hormone which maintain mineral metabolism.
(a) Parathormone
(b) Thymosin
(c) Thyroxine
(d) Melatonin
Answer:
(a) Parathormone

Question 4.
Among the following, which one is attached to the hypothalamus.
(a) Pineal
(b) Pituitary
(c) Thymus
(d) Thyroid
Answer:
(b) Pituitary

Question 5.
Stem elongation affected by:
(a) Gibberellin and Florigen
(b) Florigen and Kinn
(c) Kinn and Auxin
(d) Auxin and Gibberellin
Answer:
(d) Auxin and Gibberellin

Question 6.
Which of the following is not natural occuring plant hormone?
(a) 2, 4-D
(b) Cytokinin
(c) Gibberellin
(d) IAA
Answer:
(a) 2, 4-D

Question 7.
Leaf fall occur when the content of:
(a) Auxin increases
(b) Auxin decreases
(c) Abscisic acid decreases
(d) Gibberellin acid decreases
Answer:
(b) Auxin decreases

Question 8.
Indole acetic add generally inhibits the growth of:
(a) Root
(b) Leaves
(c) Shoots
(d) Plants in general
Answer:
(a) Root

Question 9.
Hormones are chemically:
(a) Amino acid
(b) Protein
(c) Steroid
(d) All
Answer:
(d) All

Question 10.
Pituitary gland is under the control of:
(a) Hypothalamus
(b) Adrenal gland
(c) Pineal gland
(d) Thyroid
Answer:
(a) Hypothalamus

Question 11.
Hypothyroidism in adults causes:
(a) Addison’s disease
(b) Myxoedema
(c) Sterility
(d) Cretinism
Answer:
(b) Myxoedema

Question 12.
Parathormone deficiency in man causes:
(a) Hyper calcaemia
(b) Hypo calcaemia
(c) Goitre
(d) All
Answer:
(b) Hypo calcaemia

Question 13.
The function of norepinephrine is:
(a) Almost similar to epinephrine
(b) Similar to ADH
(c) Opposite to epinephrine
(d) Opposite to ADH
Answer:
(a) Almost similar to epinephrine

Question 14.
Adrenalin increases:
(a) Heart beat
(b) Blood pressure
(c) Both (a) and (b)
(d) None
Answer:
(c) Both (a) and (b)

Question 15.
Hormone responsible for ovulation is:
(a) LH
(b) GSH
(c) Progesterone
(d) Testosterone
Answer:
(a) LH

Question 16.
Which hormone is responsible for milk ejection after the birth of baby?
(a) Progesterone
(b) Prolactin
(c) Oxytocin
(d) Oestrogen
Answer:
(c) Oxytocin

Question 17.
The islets of Langerhans are found in:
(a) Pancreas
(b) Stomach
(c) Liver
(d) Alimentary canal
Answer:
(a) Pancreas

II. Fill in the blanks:

1. Gibbereilin promotes cell division and elongation in ………, ………. and ………
2. Abscisic acid controls ……….
3. ………. is called as ‘Master gland’ of the body.
4. Growth hormone is produced in …………
5. Urine concentration is controlled by …………
6. The two lobes of thyroid glands are joined by horizontal connection called …………
7. Insulin are secreted by ……….. cells.
8. Progesterone maintains ……….. pregnancy.
9. The normal blood glucose level is ………… mg/100 ml of blood.
10. ………… converts glycogen into glucose.
11. ………… is responsible for growth of female reproductive organs.
12. Anti-inflammatory hormone is ……….
13. ……….. hormone stimulates the growth of mammary gland.
14. …….. helps in reabsorption of water.
15. Endocrine glands are ………. glands.
Answer:
1. Roots, stem and leaves
2. Leaf fall and dormancy
3. Pituitary
4. Pituitary
5. ADH
6. isthumus
7. Beta
8. normal
9. 80 – 120
10. Glucogon
11. oestrogen
12. Cortisone
13. LTH
14. Oxytocin
15. duct less

III. Match the following:

Question 1.
Match the Column I with Column II.

Answer:
A. (iii)
B. (i)
C. (ii)
D. (iv)
E. (v)

Question 2.
Match the Column I with Column II.

Answer:
A. (iii)
B. (v)
C. (ii)
D. (i)
E. (iv)

IV. State whether True or false, If false write the correct statement.

1. Bakacae disease or Foolish seedling disease in cucurbits.
2. Synthesis of ethylene occurs during ripening of fruits.
3. The secretion of Neurohypophysis are secretions of part of only pituitary.
4. Excess production of GH in children result in dwarfism.
5. Cortisone stimulates the breakdown of glycogen into glucose.

Answer:

1. False – Bakacae disease or Foolish seedling disease in rice
2. True
3. False – The secretion of Neurohypophysis are secretions of part of the nervous system.
4. False – Excess production of GH in children result in Gigantism.
5. True

V. Assertion and Reasoning:

Direction: In each of the following questions a statement of assertion (A) is given and a corresponding statement of reason (R) is given just below it. Mark the correct statement as.
Question 1.
Assertion (A): Ethylene is a plant hormone, which can transfer from one plant to another plant.
Reason (R): Ethylene is a gaseous hormones in plants.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(a) If both A and R are true and R is correct explanation of A.

Question 2.
Assertion (A): Senescence is induced by the application of cytokinin in plants.
Reason (R): Cytokinin promotes the degradation of chlorophyll and nucleic acids.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(d) Both A and R are false.

Question 3.
Assertion (A): ABA plays an important role in plants during water stress.
Reason (R): ABA promotes stomatal closing during water stress.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(a) If both A and R are true and R is correct explanation of A.

Question 4.
Assertion (A): Gibberellin is a bolting hormone.
Reason (R): Gibberellin induces parthenocarpy in fruits.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(d) Both A and R are false.

Question 5.
Assertion (A): Bolting effect in plants is performed by Gibberellin.
Reason (R): Gibberellin induce internode elongation.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(a) If both A and R are true and R is correct explanation of A.

Question 6.
Assertion (A): Vasopressin is a new hormone.
Reason (R): Vasopressin is synthesized by pars nervosa of pituitary glands.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(c) A is true but R is false.

Question 7.
Assertion (A): Hormones are said to be similar to enzyme in action and chemical nature.
Reason (R): Hormones and enzymes are proteinaceous in nature and act as informational nature.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(d) Both A and R are false.

Question 8.
Assertion (A): Deficiency of insulin produce polyuria condition.
Reason (R): Glucogon is antagonistic hormone of insulin.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(b) If both A and R are true but R is not the correct explanation of A.

Question 9.
Assertion (A): Epinephrine and nor-epinephrine are secreted by adrenal medulla are called emergency hormone.
Reason (R): These hormones rapidly mobilize the body to face a stress or emergency situation.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(a) If both A and R are true and R is correct explanation of A.

Question 10.
Assertion (A): Ovaries are both cytogenic and endocrine.
Reason (R): Ovaries produce ovum and reproductive hormone.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(a) If both A and R are true and R is the correct explanation of A.

VI. Answer in a word or sentence:

Question 1.
What is apical dominance?
Answer:
The auxins produced by the apical buds suppress the growth of lateral bud is called apical dominance.

Question 2.
Name the types of Auxins.
Answer:

• Natural Auxins – The Auxins produced by plants.
• Synthetic Auxins – Artificially synthesized auxins.

Question 3.
Write the chemical composition of thyroxine?
Answer:
Thyroxine is an iodinated protein, composed of the amino acid, tyrosine and iodine.

Question 4.
When does the maximum synthesis of ethylene occur?
Answer:
Maximum synthesis of ethylene occurs during the ripening of fruits like apples, bananas and melons.

Question 5.
In which condition the excess of dilute urine is produced? Name the disease.
Answer:
Due to less production of ADH, excess of dilute urine is produced, it causes diabetes insipidus.

Question 6.
Name the two distinct parts of adrenal.
Answer:
Adrenal cortex and adrenal medulla.

Question 7.
What are the target organs?
Answer:
The hormones, which are produced in minute quantities, act on specific organs which are called as target organs.

VII. Short Answer Questions:

Question 1.
Name the layers of the adrenal cortex.
Answer:
The adrenal cortex consists of three layers of cells called zono glomerulosa, zona fasciculata and zona reticularis.

Question 2.
Write any three physiological effects of Auxins.
Answer:

• Auxins promote the elongation of stems and coleoptiles.
• Auxins prevent the formation of abscission layer.
• Auxins induce root formation at low concentration and inhibit it at higher concentration.

Question 3.
Which hormone is called as life-saving hormone? Why?
Answer:
The cortisol hormones is called as life saving hormone. The cortisol hormones of adrenal cortex serves to maintain the body in living condition and recover it from the severe effects of stress reaction. Thus an increased output of cortisol is life saving in shock conditions.

Question 4.
Name the endocrine glands present in human and other vertebrates.
Answer:

• Pituitary gland
• Thyroid gland
• Parathyroid gland
• Pancreas (Islets of Langerhans)
• Adrenal gland (Adrenal cortex and Adrenal medulla)
• Gonads (Testes and Ovary)
• Thymus gland.

Question 5.
Write the functions of thymosin.
Answer:

1. It has a stimulatory effect on the immune function.
2. It stimulates the production and differentiation of lymphocytes.

Question 6.
Which endocrine gland is called “Master gland”? Why?
Answer:
Pituitary gland. The pituitary gland forms the major endocrine gland in most vertebrates. It regulates and controls other endocrine glands and so it is called “Master gland”.

Question 7.
Differentiate Hyperglycemia and Hypoglycemia.
Answer:

Question 8.
Write any three physiological effects of Gibberellins.
Answer:

• Elongation of internodes.
• Promote the production of male flowers in monoecious plants.
• Break dormancy of potato tubers.

VIII. Long Answer Questions:

Question 1.
Write the functions of thyroid hormones.
Answer:
The functions of thyroid hormones are:

1. Production of energy by maintaining the Basal Metabolic Rate (BMR) of the body.
2. Helps to maintain normal body temperature.
3. Influences the activity of the central nervous system.
4. Controls growth of the body and bone formation and development of gonads.
5. Essential for normal physical, mental and personality development. It is also known as personality hormone.
6. Regulates cell metabolism.
7. Increases oxygen consumption in tissues.

Question 2.
List out the hormones secreted by Adenohypophysis of pituitary-Explain any two.
Answer:

1. Growth Hormone
2. Thyroid-stimulating Hormone
3. Adrenocorticotropic Hormone
4. Gonadotropic Hormone which comprises the Follicle Stimulating Hormone and Luteinizing Hormone
5. Prolactin

Thyroid-stimulating hormone (TSH) : TSH controls the growth of thyroid gland, coordinates its activities and hormone secretion.

Adrenocorticotropic hormone (ACTH) : ACTH stimulates adrenal cortex of the adrenal gland for the production of its hormones. It also influences protein synthesis in the adrenal cortex.

Question 3.
Explain the testes and its functions.
Answer:
Testes are the reproductive glands of the males. They are composed of ‘ seminiferous tubules, leydig cells and sertoli cells. Leydig cells form the endocrine part of the testes. They secrete the male sex hormone called testosterone.
Functions of testosterone:

1. It influences the process of spermatogenesis.
2. It stimulates protein synthesis and controls muscular growth.
3. It is responsible for the development of secondary’ sexual characters (distribution of hair on body and face, deep voice pattern, etc).

Question 4.
Write the physiological effects of cytokinin.
Answer:

1. Cytokinin induces cell division (cytokinesis) in the presence of auxins.
2. Cytokinin also causes cell enlargement.
3. Both auxins and cytokinins are essential for the formation of new organs from the callus in tissue culture (Morphogenesis).
4. Cytokinins promote the growth of lateral buds even in the presence of apical bud.
5. Application of cytokinin delays the process of ageing in plants. This is called Richmond Lang effect.

IX. Higher Order Thinking Skills: (HOTS)

Question 1.
You are given a tissue with its potential for differentiation in an artificial culture. Name the hormones to be added to the medium to secure shoots as well as roots.
Answer:
The hormones to be added to the medium are gibberellin and abscisic acid.

Question 2.
Insulin and thyroxine arrive at an organ at the same time. Thyroxine causes an effect on the organ but insulin does not. This is because:
Answer:
The organ’s cells have receptors for thyroxine but not for insulin.

Question 3.
A person entering an empty room suddenly finds a snake right in front on opening the door. What changes happen in his neuro-hormonal control system?
Answer:
Sympathetic nervous system is activated releasing epinephrin and norepinephrine from adrenal medulla.

Question 4.
A pregnant female delivers a baby who suffers from stunted growth, mental retardation, low intelligence quotient and abnormal skin. This is the result of:
Answer:
Deficiency of iodine in diet.

Question 5.
A patient of diabetes mellitus excretes glucose in urine even when he kept in a carbohydrate free diet. It is because:
Answer:
Fats are catabolised to form glucose.

Question 6.
Dr. F went noted that if Coleoptile tips were removed and placed on agar for one hour, the agar would produce a bending when placed on one side of freshly cut coleoptile stumps. What is the significance of this experiment.
Answer:
The experiment demonstrated the polar movement of Auxin.

Students can download 10th Social Science Geography Chapter 6 Physical Geography of Tamil Nadu Questions and Answers, Notes, Samacheer Kalvi 10th Social Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Social Science Solutions Geography Chapter 6 Physical Geography of Tamil Nadu

Samacheer Kalvi 10th Social Science Physical Geography of Tamil Nadu Text Book Back Questions and Answers

I. Choose the correct answer

Question 1.
The latitudinal extent of Tamil Nadu is:
(a) 8°4’N to 13°35’N
(b) 8°5’S to 13°35’S
(c) 8°0’N to 13°5’N
(d) 8°0’S to 13°05’S
Answer:
(a) 8°4’N to 13°35’N

Question 2.
The longitudinal extent of Tamil Nadu is …………………
(a) 76°18′ E to 80°20’E
(b) 76° 18′ W to 80°20′ W
(c) 86°18’Eto 10°20’E
(d) 86°18′ W to 10°20′ W
Answer:
(a) 76°18′ E to 80°20’E

Question 3.
The highest peak in Tamil Nadu is:
(a) Anaimudi
(b) Doddabetta
(c) Mahendragiri
(d) Servarayan
Answer:
(b) Doddabetta

Question 4.
Which of the following passes is not located in the Western Ghats of Tamil Nadu?
(a) Palghat
(b) Shencottah
(c) Bhorghat
(d) Achankoil
Answer:
(c) Bhorghat

Question 5.
Which one of the following rivers is flow into the Arabian Sea?
(a) Periyar
(b) Cauvery
(c) Chittar
(d) Bhavani
Answer:
(a) Periyar

Question 6.
The district with largest mangrove forest cover in Tamil Nadu is ……………
(a) Ramanathapuram
(b) Nagapattinam
(c) Cuddalore
(d) Theni
Answer:
(c) Cuddalore

Question 7.
The forest cover of Tamil Nadu as per 2017 Indian Forest Report is:
(a) 20.21%
(b) 20.31%
(c) 21.20%
(d) 21.30%
Answer:
(a) 20.21%

Question 8.
Retreating monsoon wind picks up moisture from …………….
(a) Arabian sea
(b) Bay of Bengal
(c) Indian Ocean
(d) Timor sea
Answer:
(b) Bay of Bengal

Question 9.
hich of the following district is affected by sand dunes to a large extent?
(a) Theni
(b) Madurai
(c) Thanjavur
(d) Ramanathapuram
Answer:
(d) Ramanathapuram

Question 10.
The district which has the largest forest cover in Tamil Nadu is ………………
(a) Dharmapuri
(b) Vellore
(c) Dindigul
(d) Erode
Answer:
(a) Dharmapuri

II. Fill in the blanks

1. The plateau which lies between the Nilgiris and Dharmapuri districts is ………………
2. ……………… is the highest peak in the southern most part of the Eastern Ghats.
3. The riverine Island of Srirangam is located between ……………… and ……………… branches of cauvery.
4. ……………… soil is suitable for the cultivation of tea and coffee plants.
5. ……………… is the Tamil Nadu state animal which is found in ………………

Answers:

1. Coimbatore
2. Solaikaradu
3. Northern (Coleroon or Kollidam), and Southern (Cauvery)
4. Laterite
5. Nilgiri Tahir, Western Ghats, Tamil Nadu and Kerala

III. Match the following

Answer:
A. (iv)
B. (iii)
C. (ii)
D. (v)
E. (i)

IV. Assertion type Question

Question 1.
Assertion (A): Tamil Nadu does not receive much rainfall from southwest monsoon.
Reason (R): It is situated in the rain shadow area of the Western Ghats.
(a) Both (A) and (R) are true and (R) explains (A).
(b) Both (A) and (R) are true but, (R) does not explain (A).
(c) (A) is true but, (R) is false.
(d) (R) is true but, (A) is false.
Answer:
(a) Both (A) and (R) are true and (R) explains (A).

Question 2.
Assertion (A): Red soil is rich in iron oxides.
Reason (R): It is formed by leaching.
(a) Both (A) and (R) are true and (R) explains (A).
(b) Both (A) and (R) are true but, (R) does not explain (A).
(c) (A) is true but, (R) is false.
(d) (R) is true but, (A) is false.
Answer:
(c) (A) is true but, (R) is false.

V. Answer the following in brief

Question 1.
State the boundaries of Tamil Nadu.
Answer:
Tamil Nadu is surrounded by the Bay of Bengal in the east, Indian ocean in the South, Kerala and Karnataka in the west and Andhra Pradesh on the North.

Question 2.
List out the districts of Tamil Nadu which are partly/fully located on Eastern and Western Ghats separately.
Answer:

• Districts of Tamil Nadu Partly / fully located on Eastern Ghats and Western Ghats.
• Districts on Eastern Ghats: Vellore, Thiruvannamalai, Salem, Nammakal, Trichirapalli, Perambalur.
• Districts on Western Ghats: Nilgiris, Kanyakumari, Dindigul, Virudhunagar.

Question 3.
What is ‘Teri??
Answer:
The sand dunes formed along the coast of Ramanathapuram and Thoothukudi districts are called Teri.

Question 4.
How is coastal plain formed?
Answer:
Coastal plains is formed by die rivers that flow towards east and drain in the Bay of Bengal in Tamil Nadu. It is more than 80 kilometers wide at some places.

Question 5.
Name the major islands of Tamil Nadu.
Answer:
Pamban, Hare, Krusadai, Nallathanni Theevu, Pullivasal, Srirangam, Upputanni, Island Grounds, Kattupalli Island, Quibble Island and Vivekananda Rock Memorial are some major islands of Tamil Nadu.

Question 6.
Name the tributaries of river Thamirabarani.
Answer:
Karaiyar, Servalar, Manimuthar, Gadananathi, Pachaiyar, Chittar, and Ramanathi are the main Tributaries of Thamirabarani.

Question 7.
Define Disaster Risk Reduction.
Answer:
The concept and practice of disaster risks through systematic efforts to analyse and manage the causal factors of disasters including through reduced exposure to hazards, lessened vulnerability of people and property, wise management of land and environment and improved preparedness for adverse events.

Question 8.
During cyclone, how does the Meterological department warn the . fishermen?
Answer:
During Cyclone the Meterological Department warn the fishermen through State Government officials and broadcast of warnings through All India Radio and National Regional (Doordharshan) telecast programme. During Cyclone four stages of warning are given by the Meteorological Department to keep the fishermen alert and to return back who ventured into the sea through coast guards also.

VI. Distinguish between the following

Question 1.
Western Ghats and Eastern Ghats.
Answer:
Western Ghats (in Tamil Nadu):

1. Western Ghats extends from the Nilgiris in the North to Marunthuvazh malai at Swamithope in Kanyakumari in the South.
2. It is a continuous range.
3. Doddabetta (in the Nilgiris) is the highest peak.
4. It’s height ranges from 2000mts to 3000 mts above sea level.
5. Important hills are Nilgiris, Anaimalai and palani hills etc.

Eastern Ghats (in Tamil Nadu):

1. Major hills of the Eastern Ghats of Tamil Nadu are located in the Northern districts of the State.
2. It is discontinuous dissected at many places by the east flowing rivers.
3. Solaikaradu in the Servarayan hills is the highest peak.
4. It’s height ranges from 1,100 mts to 1600 mts above sea level.
5. Javadhu, Kalvarayan and Servarayan etc are some of the major hills.

Question 2.
Southwest monsoon and Northeast monsoon.
Answer:
Southwest Monsoon:

1. Period of Southwest monsoon is from March to May.
2. Tamil Nadu is located in the rainshadow region for the wind hence gets only less rainfall.
3. Rainfall decreases from West to East,
4. CoimbatorePlateau,Kanyakumari and Tirunelveli districts receives 50 – 100 cm rainfall during this period.

Northeast Monsoon:

1. Period of Northeast Monsoon is from October and lasts till mid – December.
2. 48% of annual rainfall to Tamil Nadu is from this wind.
3. It is the rainy season for the districts of Tamil Nadu.
4. Coastal districts get nearly 60% of annual rainfall and interior districts get 40 – 50 cm rainfall.

Question 3.
Tropical evergreen and Tropical deciduous forests.
Answer:
Tropical Evergreen Forests:

1. This types of forest is found in the areas of heavy rainfall.
2. It is dense, multilayered forest.
3. The major type of trees found in the forests are Cinnamon, Malabar ironwood kindal, jamun etc.
4. It is found in the upper slopes of Western Ghats of Tirunelveli, Kanyakumari, Nilgiris and Coimbatore districts.

Tropical Deciduous Forests:

1. It is found in the regions of sub tropical climate with moderate rainfall.
2. The trees in this forest shed their leaves during dry season.
3. The major trees are kapok, kadamba, axle wood, bamboo, dog- teak, silk cotton etc some trees are economically important.
4. It is found in the margin of semi evergreen and evergreen forests – Servarayan, Kollimalai, Pachaimalai Eastern Ghats.

VII. Give reasons for the following

Question 1.
Eastern Ghats are not a continuous range.
Answer:
Eastern Ghats is a discontinuous and irregular one. It is dissected at many places by the rivers, which drain into the Bay of Bengal. Its height ranges from 1,100 to 1,600 metres.

Question 2.
Tamil Nadu receives low rainfall during Southwest monsoon.
Answer:
Tamil Nadu is located in the rainshadow region for the wind which blows from the Arabian sea. As a result Tamil Nadu receives low rainfall during Southwest monsoon.

Question 3.
Alluvial soil is fertile.
Answer:
Alluvial soil are formed by the deposition of silt by the rivers. Alluvial soils are generally fertile as they are rich in minerals such as lime, potassium, magnesium, nitrogen and phosphoric acid. It is deficient in nitrogen and humus. It is porous and loamy.

Question 4.
Cuddalore is a multiprone disaster zone.
Answer:
Cuddalore is a multiprone disaster zone, because it is located under the very high cyclone prone zone and flood prone zone. More over it is an coastal area often affected by the vulnerable natural disasters.

VIII. Answer the following in a paragraph

Question 1.
Describe the nature of the plateau region of Tamil Nadu.
Answer:

• Plateau of Tamil Nadu is located between the Western Ghats and the Eastern Ghats.
• It is roughly triangular in shape and covers an area of about 60,000 sq. km.
• Its height increases from east to west. Its height ranges between 150 and 600 m.
• This plateau is broader in the north and very narrow in the south and it has many subdivisions.
• Bharamahal plateau is a part of the Mysore plateau situated in the northwestern part of Tamil Nadu. Dharmapuri and Krishnagiri districts are located in this region.
• Coimbatore plateau lies between the Nilgiris and Dharmapuri districts. Its height varies from 150 to 450 metres. Moyar river separates this plateau from the Mysore plateau.
• Rivers like Bhavani, Noyyal and Amaravathi, which originate from Western Ghats form Valleys in the region. Many intermontane plateaus are found in the region of the Nilgiris. Sigur plateau is one such plateau.
• Madurai plateau found in Madurai district extends up to the foothills of the Western Ghats. Vaigai and Thamirabarani basins are located in the zone.

Question 2.
Write an account on river Kaveri.
Answer:
Origin of River Kaveri: The river Kaverioriginates in the Brahmagiri hills of Kodagu (coorg) district of Karnataka in the Western Ghats. It serves as the boundary between Karnataka and Tamil Nadu for a distance of 64 k.m.

Length of its course in Tamil Nadu: 416 km

Upper course: It enters into Tamil Nadu in the form of Hogenakkal falls in Dharmapuri district. Mettur Dam (Stanely Reservoir) is built across the river in Salem District. A tributary called Bhavani joins Cauvery on the right bank about 45 km from the Mettur Reservoir.

Middle course: Then it takes easterly direction to enter into the plains of Tamil Nadu.

1. At Thirumukkudal 10 km from Karur, two more tributaries Noyyal and Amaravathi confluence the river on the right bank. In this region the river is wider and called ‘Agandra Cauvery’.
2. In Tiruchirappalli the river branches into two. The Northern branch is called Coleroon or Kollidam and the Southern branch remains Cauvery. After flowing for about 16 km, the two branches join again to form the ‘Srirangam Island’.
3. The Grand Anaicut, called as Kallanai was built across the river Cauvery. The deltaic stage begins in the middle course.

Lower course: After Kallanai the river breaks into a large number of distributaries and forms a network all over the delta. River Cauvery merges into Bay of Bengal to the South of Cuddalore.

Question 3.
Explain the characteristic features of summer and winter seasons of Tamil Nadu. Summer Seasons:
Answer:
The apparent migration of the sun towards north during March, April and May result in the reception of vertical sun’s rays by South India. Thus there is a steady rise in temperature from the equator. Hence, Tamil Nadu located to the south of Tropic of Cancer experiences high temperature. Generally, the temperature varies from 30°C to more than 40°C. During this season particularly in the month of May, the southern part of the state receives some rainfall from pre-monsoon showers (Mango/Blossom showers) and some parts experience convectional rainfall.

Winter Seasons:
During January’ and February, the vertical rays of the sun fall between the Tropic of Capricorn and the Equator. Hence, Tamil Nadu and India on the whole receive slanting rays from the sun. So, the weather is slightly cooler during these months. The difference between summer and winter temperature is not very high. Winter temperature in Tamil Nadu varies from 15°C to 25°C. However, in the hill stations, the winter temperature drops below 5°C occasionally. Some valleys in the Nilgiris record even 0°C. This drop in temperature leads to the formation of thick mist and frost. This season is practically dry.

Question 4.
What is desertification and write about the areas affected by it in Tamil Nadu.
Answer:

1. The process by which fertile land becomes desert due to inappropriate agriculture, deforestation, and drought is termed as desertification. It is a type of land degradation which lead to the extension of desert area.
2. In Tamil Nadu Theni, the Nilgiris and Kanyakumari are the worst affected districts by desertification.
3. About 12,000 hectares (120sq. km) were affected by sand deposition in Theni and Rajapalayam.

Question 5.
Bring out the types and distribution of soils in Tamil Nadu.
Answer:
According to their characteristics, soils of Tamil Nadu are classified into five types.

Soil Types	Distribution
Alluvial soil	River valley regions and coastal plains – Thanjavur, Nagapattinam, Cuddalore, Villupuram, Tirunelveli and Kanyakumari.
Black soil	Semi arid regions – Coimbatore, Madurai, Virudhunagar, Tirunelveli and Thoothukudi.
Red soil	Cover two-third areas of Tamil Nadu – particularly in the central district and mainly in Sivagangai and Ramanathapuram.
Laterite soil	Intense leaching areas – parts of Kanchipuram, Thiruvallur and Thanjavur, patches over the mountainous region in the Nilgiris.
Saline soil	Confined to the Coromandel coast – Vedaranyam.

Question 6.
Name the areas which are affected by landslides. What will you do before, during and after landslides?
Answer:
Nilgiris in Tamil Nadu is identified as one of the most vulnerable districts in the country and landslides pose a major threat in this area. The other regions which are prone to land slides are Coimbatore and palani hill of Dindigul district where Kodaikanal hill station is located.

Before: Create awareness; stay alert and awake; monitor the news updates; make evacuation plan; listen for any unusual sounds that might indicate moving debris such as trees cracking, boulders knocking and consider leaving the place of landslide if it is safe to do so.

After: Stay away from the slide area; listen to local radio or television stations for the latest emergency information; watch for flooding, which may occur after a landslide or debris flow; check for injured and trapped persons near the slide, without entering the direct slide area.

IX. Map study

Question 1.
Mark important rivers, distribution of soil and forest types on different Tamil Nadu maps.

(a) Important rivers:

1. Cauvery
2. Palar
3. Then Pennaiyar / Ponnaiyar
4. Vaigai
5. Thamirabarani.

Other rivers:

1. Coleroon or Kollidam
2. Amaravathi
3. Bhavani
4. Noyyal
5. Cheyyar.

(b) Distribution of soil

Soil	Areas
Alluvial	Thiruvarur, Nagapattinam, Villupuram, Cuddalore, Tirunelveli, Kanyakumari and Cauvery Delta.
Black soil	Coimbatore, Madurai, Virudhunagar, Tirunelveli.
Red soil	Sivagangai, Ramanathapuram.
Laterite soil	Kancheepuram, Tiruvallur, Nilgiris.
Saline soil	Coromandel coast, Vedaranyam coast.

img 3

(c) Forest type (Natural vegetation)

1. Tropical evergreen forest: Slopes of Western Ghats Nilgiris, Coimbatore, Tirunelveli, Kanyakumari.
2. Temperature forest: Anaimalai, Palani hills.
3. Tropical deciduous forest: Eastern Ghats, Servarayan, Kollimalai, Pachaimalai.
4. Mangrove forest: Cuddalore, Chidambaram,

TB. PNo: 85
Find Out

Question 1.
Name the first state of India created on linguistic basis.
Answer:

1. Andhra Pradesh was the first State of India created on linguistic basis.
2. Bifurcated from Madras Presidency the Telugu speaking area – Andhra Pradesh on October – 1^st, 1953.

Question 2.
Why was the capital of Tamil Nadu renamed?
Answer:
After India got independence in 1947, the city became the capital of Madras state, which was renamed as Tamil Nadu on 1969. On 17 July 1996 the city known as Madras was officially renamed as Chennai.

Question 3.
What is the meaning of the word Chennai
Answer:
Face of the city.

TB. PNo: 86
Activity

Question 1.
Find out the coastal districts of Tamil Nadu with the help of a map.
Answer:
13 Districts – Thiruvallur, Chennai, Kaneheepuram, Villupuram, Cuddalore, Tiruvarur, Nagapattinam, Thanjavur, Pudukottai, Ramanathapuram, Thoothukudi, Tirunelveli and Kanyakumari are the coastal districts.

Question 2.
Group the districts of Tamil Nadu which share their boundary with the states of Andhra Pradesh, Karnataka and Kerala separately.
Answer:
Andhra Pradesh – Krishnagiri, Vellore and Tiruvallur.
Karnataka – Krishanagiri. Dharmapuri, Erode, Nilgiris.
Kerala – Nilgiris, Coimbatore, Theni, Tirunelveli, Kanyakumari, Virudhunagar.

TB. PNo: 90
Find Out

Question 1.
Why are mountain heights measured from mean sea level and not from ground level?
Answer:
(i) Ocean is one continuous water body on the earth’s surface. Its surface tend to seek the same level whatever be the landform around.
(ii) It is difficult to establish the base of the mountain from the rest of the ground around as their elevation is not the same on all sides.

Question 2.
Name the hill resorts of Western Ghats and Eastern Ghats in Tamil Nadu.
Answer:
Hill resorts of Western Ghats: Nilgiri hills, Anaimalai, Yelamalai, Varusanadu and Pothigai hills, Megamalai.
Hill resorts of Eastern Ghats: Servarayan hills, Kalvarayan hills, Pachaimalai and Kolli hills.

Question 3.
Is Ooty located on western Ghats?
Answer:
Yes.

Question 4.
Name the hill stations located in Western and Eastern Ghats of Tamil Nadu. Western Ghats:
Answer:
Ooty and coonoor – Nilgiri hills Valparai – Anaimalai hills Kodaikanal -Palani hills Kurangani -Kurangani hills (Theni)
Eastern Ghats:
Yercaud – Servarayan hills

Question 5.
Why is the Nilgiri hills called as Blue Mountains?
Answer:
Nilgiri hills are called as Blue Mountains, inspired by the Kurunji flower which blooms every twelve years giving the slopes a bluish tinge.

TB. PNo: 94
Find Out

Question 1.
What is Agni Nakshatram?
Answer:
Agni Nakshatram period marks the onset of summer season in the month of May – June a period of 21 days. Peak summer with very high temperature, scorching heat all over parts of India.

Question 2.
Group the districts of Tamil Nadu into low, moderate and heavy rainfall regions.
Answer:

Samacheer Kalvi 10th Social Science Physical Geography of Tamil Nadu Additional Important Questions and Answers

I. Choose the correct answer

Question 1.
Initially after bifurcation in Madras State there were only ………………. districts.
(a) 13
(b) 14
(c) 15
(d) 16
Answer:
(a) 13

Question 2.
Tamil Nadu lies in the ……………. part of India.
(a) Northeast
(b) Southwest
(c) Southeast
Answer:
(c) Southeast

Question 3.
Palk Strait and Gulf of Mannar separates Tamil Nadu from :
(a) Andaman and Nicobar Island
(b) Lakshadweep Island
(c) Nepal
(d) Srilanka
Answer:
(d) Srilanka

Question 4.
…………… hill is located in Eastern Ghats.
(a) Nilgiri
(b) Kalrayan
(c) Palani
Answer:
(b) Kalrayan

Question 5.
Tamil Nadu has Loksabha constituencies.
(a) 19
(b) 92
(c) 39
(4)21
Answer:
(c) 39

Question 6.
Mukuruthi is a peak located in the …………….
(a) Eastern Ghats
(b) Nilgiri Hills
(c) Palani Hills
Answer:
(b) Nilgiri Hills

Question 7.
The highest peak in Palani hills is :
(a) Vembadi Shola
(b) Vandaravu
(c) Doddabetta
(d) Ooty
Answer:
(b) Vandaravu

Question 8.
Mangrove forests are found in …………….
(a) Vedaranyam
(b) Coimbatore
(c) Nilgiris
Answer:
(a) Vedaranyam

Question 9.
………………. hills separate Vellore and Tiruvanamalai districts.
(a) Kolli
(b) Andipatti
(c) Pothigai
(d) Javadhu
Answer:
(d) Javadhu

Question 10.
…………. hills seperates Vellore and Thiruvanamali districts.
(a) Pothigai
(b) Andipatti
(c) Javadhu
Answer:
(c) Javadhu

Question 11.
Bharamahal Plateau is a part of ………………. Plateau.
(a) Mysore
(b) Chota Nagpur
(c) Maharashtra
(d) Madurai
Answer:
(a) Mysore

Question 12.
……………. helps in the prevention of coastal erosion from waves and stroms.
(a) Mangroves
(b) trees
(c) Land slide
Answer:
(a) Mangroves

Question 13.
………………. is one of the main tributary of Thamirabarani.
(a) Noyyal
(b) Amaravathi
(c) Moyar
(d) Manimuthar
Answer:
(d) Manimuthar

Question 14.
Tamil Nadu depends mostly on ……………… monsoon.
(a) South west
(b) Northeast
(c) Cyclone
Answer:
(b) Northeast

Question 15.
About ………………… % of the total area of the Tamil Nadu is drought prone.
(a) 26
(b) 62
(c) 64
(d) 46
Answer:
(c) 64

II. Fill in the blanks

1. ………………. is the branch of geography that deals with different physical aspects like landform soil etc.
2. For a short time Tamil country was ruled by the ………………. not much known.
3. Tamil Nadu coast is the second longest in India after ……………….
4. Kallakurichi, Thenkasi and ………………. are the newly formed districts of Tamil Nadu.
5. Our state has ………………. Assembly Constituencies.
6. All districts of Tamil Nadu except the ………………. the Nilgiris and Kanyakumari were bifurcated at different points of time.
7. The Nilgiri hills consists ………………. peaks with more than 2000 metres.
8. ………………. hills are located to the South of Palghat gap.
9. ISRO propulsion complex is situated on the lower slopes of ……………….
10. Vainu Bappu Observatory is in ……………….
11. The Kalvarayan hills separates the river basins of ……………….
12. The name Kalvarayan came from the name of ancient tribes.
13. ………………. temple an important pilgrim centre is located on Kolli hills range.
14. ………………. river separates Coimbatore plateau and Mysore plateau.
15. ………………. is one of the intermontane plateau found in the region of Nilgiri hills.
16. ………………. are found at the head of Gulf of Mannar in the East Coastal regions.
17. The Reservoir of ………………. is called Stanely Reservoir.
18. The network of distributaries of River Cauvery is called ……………….
19. Palar river enters into Bay of Bengal near ……………….
20. The origin of Thamirabarani river is associated with sage ……………….
21. Pre monsoon showers are also known as ………………. showers.
22. Black soil is also known as ……………….
23. ………………. reduces the fertility of the soil.
24. Trees of ………………. forests are economically important.
25. ………………. is the second largest Mangrove forest in the world found in Tamil Nadu.
26. Koonthankulam bird sanctuary is in ………………. district.
27. Pulicat lake bird sanctuary is in ………………. district.
28. A sudden natural catastrophe that causes great damage or less to lives and properties is called ……………….
29. The number of Municipal Corporations in Tamil Nadu is ……………….
30. Ancient Gondwana land broke away 135 years ago during ………………. period.
31. ………………. hills are the eastward extension of Western Ghats.
32. Coastal plains of Tamil Nadu extend from ………………. to ……………….
33. The ………………. coast along the Bay of Bengal consists of many beautiful exotic beaches.
34. ………………. of Tamil Nadu are its life line.
35. Except ………………. river all the other rivers of Tamil Nadu state are non – perennial.
36. Palar river originates beyond ………………. village in Kolar district of Karnataka.
37. The ………………. river is extensively dammed for irrigation especially in Tamil Nadu.
38. The surplus water in Vaigia river is discharged into ………………. tank.
39. The colour of the Red soil is due to the presence of high content of ……………….
40. ………………. soil is suitable for tea and coffee plants.
41. The systematic efforts taken to reduce the risks during disasters is ……………….
42. Water is the most common trigger of a ……………….
43. Tamil nadu was the worst affected state by the flood occured in ……………….

Answers:

1. Physical geography
2. Kalabras
3. Gujarat
4. Chengalpet
5. 234
6. Chennai
7. 24
8. Anaimalai
9. Mahendragiri hills
10. Kavalur
11. Cauvery and Palar
12. Karalar
13. Arapaleeswarar
14. Moyar
15. Slgur
16. Coral rocks
17. Mettur Dam
18. Garden of Southern India
19. Kuvattur
20. Agasthiyar
21. Mango I Blossm
22. Regur soil
23. Soll erosion
24. Tropical Deciduous forest
25. Pichavaram mangrove forest
26. Tirunelveli
27. Trruvallur
28. Disaster
29. 15
30. cretaceous
31. Palam
32. Chennai, Kanyakumari
33. Coromandel Coast
34. Rivers
35. Tharnirabarani
36. Talagavara
37. Then pennaiyar/ Then ponnaiyar
38. Ramnad big tank
39. Iron Oxides
40. Laterite
41. Disaster Risk Reduction
42. landslide
43. 2015

III. Match the following

Question 1.
Match the Column I with Column II.


Answer:
A. (v)
B. (i)
C. (iv)
D. (ii)
E. (iii)

Question 2.
Match the Column I with Column II.

Answer:
A. (iv)
B. (v)
C. (ii)
D. (iii)
E. (i)

Question 3.
Match the Column I with Column II.

Answer:
A. (iii)
B. (v)
C. (iv)
D. (i)
E. (ii)

Question 4.
Match the Column I with Column II.

Answer:
A. (iii)
B. (v)
C. (iv)
D. (i)
E. (ii)

IV. Assertion type question

Question 1.
Assertion (A): Tamil Nadu state was reorganised several times even recently.
Reason (R): For the purpose of administrative convenience.
(a) Both (A) and (R) are true but R does not explain (A).
(b) (A) is true but (R) is false.
(c) (A) is false but(R) is true.
(d) Both (A) and (R) are true and (R) explains (A).
Answer:
(d) Both (A) and (R) are true and (R) explains (A).

Question 2.
Assertion (A): Pothigai hills are called by different names.
Reason (R): It has rich evergreen forest, waterfalls and Ancient temples.
(a) Both (A) and (R) are correct (R) explains (A).
(b) (A) is true but (R) is false.
(c) (A) is false but (R) is true.
(d) Both (A) and (R) are true but (R) does not explains (A).
Answer:
(d) Both (A) and (R) are true but (R) does not explains (A).

Question 3.
Assertion (A): Yercaud is known as poor man’s Ooty.
Reason (R): It is on the Kolli hills.
(a) (A) is true (R) is false
(b) (A) is false (A) is true
(c) Both (A) and (R) are true (R) explains (A).
(d) Both (A) and (R) are true but (R) does not explains (A).
Answer:
(a) (A) is true (R) is false

Question 4.
Assertion (A): Tamil Nadu experiences mild tremor.
Reason(R): The state is located in the moderately low risk seismic zone.
(a) (A) is true (R) is false.
(b) Both (A) and (R) are true (R) explains (A).
(c) (A) is false (R) is true.
(d) Both (A) and (R) are true but (R) does not explains (A).
Answer:
(b) Both (A) and (R) are true (R) explains (A).

V. Answer the following in brief

Question 1.
What do you know about the land features of Tamil Nadu?
Answer:
Tamil Nadu has many unique land features that include high eroded mountains. Shallow deep valleys and plains. The topography of the State slopes towards east.

Question 2.
Mention the Latitudinal and Longitudial extent of Tamil Nadu.
Answer:
Tamil Nadu extends 8° 4′ N to 13° 35′ N latitudes and from 76° 18′ E to 80° 20′ E longitudes.

Question 3.
Name the hills of Western Ghats in Tamil Nadu.
Answer:
The Nilgiris, Anaimalai, Palani hills, Cardomom hills, Varusanadu, Andipatti and Agasthiyar hills.

Question 4.
Name the major physical divisions of Tamil Nadu.
Answer:

• Western Ghats
• Eastern Ghats
• Plateaues
• Coastal plains and
• Inland plains

Question 5.
What are the other names of Pothigai hills?
Answer:
Pothigai hills are called by different names such as Shiva Jothi Parvath, Agasthiyar hills and Southern Kailash.

Question 6.
Name the rivers that flow in the South Of Tamil Nadu?
Answer:

• Vaigai (Madurai)
• Vaippar (Virudhunagar)
• Thamirabarani (Thirunelveli)
• Kodaiyar (Kanyakumari) flows in the south of Tamil Nadu.

Question 7.
What do you mean by Coriolis Force?
Answer:
‘Coriolis Force” refers to the apparent force acts as a result of the earth’s rotation deflects the moving objects (such as projectiles or air currents) to the right in the Northern hemisphere and to the left in the Southern hemisphere. It is one of the main reason for the movement of the monsoon winds originates from the Indian Ocean.

Question 8.
Define Soil.
Answer:

• Soil is a loose material
• It forms the uppermost layer of the earth.
• It is essential for the development of agriculture.

Question 9.
Define soil and its significance.
Answer:
Soil is the loose material mainly formed by the weathering and erosion rocks. It forms an important elements of agriculture. It provides essential minerals and nutrients for the growth vegetation.

Question 10.
Bring out the significance of Kallanai in Tamil Nadu.
Answer:

1. Kallanai built around first century, by Karikalan is still in use.
2. It is considered to be the oldest water regulatory structure in the world.

Question 11.
What are all major factors that control the distribution of natural vegetation?
Answer:
Landforms, nature of the soil, temperature, rainfall and skspe of the relief features are the major factors that control the distribution of natural vegetation.

Question 12.
What is the role played by the mangroves in coastal zone management?
Answer:

1. Mangroves help in the prevention of coastal erosion from waves and storms.
2. It also protects coral reefs and sea grass meadows from being smothered in sediments.

Question 13.
Where the mangrove forests are found in general?
Answer:
In general the mangrove forests are found in the coastal areas, river deltas, tails of islands and over sea faces where accretion is in progress.

Question 14.
Name the places in Tamil Nadu where mangrove forest is found to a considerable extent.
Answer:
Pichavaram, Vedaranyam, Muthupet, Chatram and Thoothukudi are the places in Tamil Nadu where the mangrove forest is found to a considerable extent.

Question 15.
Name the three major Biosphere reservation in Tamil Nadu.
Answer:
The three major Bio – sphere Reservation in Tamil Nadu are:

1. Nilgiris Biosphere Reserve
2. Gulf of Mannar Biosphere Reserve (marine)
3. Agasthiyarmalai Biosphere Reserve

Question 16.
What does Disaster Risk Reduction include?
Answer:
The Disaster Risk Reduction includes:

1. Reducing exposure to hazards.
2. Lessening the vulnerability of people and property.
3. Wise management of land and environment.
4. Improving preparedness and early warning for adverse events.

Question 17.
How does the Government classify the ground water blocks?
Answer:

1. 145 out of 385 are classified as safe ground water blocks.
2. The others are in various stages of depletion such as over exploited, critical and semi-critical.
3. 2% of the blocks are saline and 64% of total area of the state is drought probe.

VI. Distinguish between the following

Question 1.
Distinguish between the plains and plateaus of Tamil Nadu.
Answer:
Plains:

1. Plains of Tamil Nadu is divided into Inland plains and Coastal Plains.
2. Inland plains are formed by the rivers of Tamil Nadu coastal plains are formed along the Bay of Bengal coast by the lower course of the river.
3. Height increases from West to East.
4. It covers the districts of Salem, Erode, Karur, Trichy, Thanjavur, Thiruvarur and Nagapattinam.

Plateaus:

1. Plateaus are subdivided into three – Dharmapuri plateau, Coimbatore plateau and Madurai plateau.
2. Plateaus are oldest region formed by the disintegration of lava rocks and they are located between Western Ghats and Eastern Ghats.
3. Height increases from East to West.
4. Dharmapuri, Krishnagiri, Coimbatore, Nilgiris, Salem and Madurai are the districts lie in the plateau region.

Question 2.
Summer season and winter season in Tamil Nadu.
Answer:
Summer season:

1. Period of summer season begins from March – May.
2. Much variation in summer temperature increases from South to North (30°C – 40°C).
3. Pre monsoon showers and convection rainfall occurs in this season.

Winter season:

1. Period of winter season is from January – February.
2. Not much difference in winter temperature (15°C – 25°C).
3. Generally this season is dry.

Question 3.
Black soil and Alluvial soil.
Answer:
Black soil:

1. Its formation is by weathering of igneous rocks.
2. Clayey in nature when wet develop cracks when dry.
3. Cotton grows well in this soil.
4. It is developed over the Deccan lava granite region under semi arid condition.
5. Found in the districts of Coimbatore, Madurai, Tirunelveli, Virudhunagar.

Alluvial soil:

1. Formed by the deposition of silt by the rivers.
2. Fertile in nature as they are rich in minerals.
3. Paddy and sugar cane grows well in this soil.
4. It is found in the river valley regions and the coastal planis.
5. Found in the districts of Thanjavur, Tiruvarur, Nagapattinam, Cuddalore.

Question 4.
Montane Temperature forest and Tropical Thorn forest.
Answer:
Montane Temperature Forest:

1. Found over an altitude of 1000 mts in sheltered valleys of Anaimalai, Nilgiris and Palani hills.
2. Trees in these forest are evergreen and usually short.
3. Nilgiri champa, wights litsea and rose apple are the common trees.

Tropical Thom Forest:

1. Found where there is little rainfall from plains up to 400 mts altitude.
2. Trees are sturdy and withstand dry condition. Shmbs are common.
3. Palm, neem, rusty acacia, wheel are some of the varieties.

VII. Give reasons for the following

Question 1.
Black soil is also known as Black cotton soil.
Answer:

1. Black soil retails moisture which is very essential for yarning of thread.
2. As cotton grows well in this soil, it is also known as black cotton soil.

Question 2.
It is necessary to conserve the soil resources with intensive care.
Answer:

1. Soil forms the basis mainly for agriculture and other purposes. It is a non-renewable resource and difficult to replace it once it gets degraded.
2. Soil erosion reduces the fertility of the soil which in turn reduces agricultural productivity. So it is necessary to take intensive care to conserve the soil resources.

Question 3.
It is necessary to aware the measures to be adopted during different types of natural disasters.
Answer:
The alteration of natural environment by the technology and developmental activities increase the frequency of disaster all over the world. So it is necessary to aware the measures to be adopted during different types of natural disasters.

Question 4.
Tamil Nadu Government has banned trekking in the state for two months every year (Feb -15 to April 15).
Answer:

1. The high temperature during summer leads to occasional forest fire in deciduous and thorn forests in Tamil Nadu.
2. 23 people were killed as they were stuck in the forest fire at Kurangani hills while trekking. On March 11th, 2018.
3. Thus in the aftermath of this incident made the Tamil Nadu Government to ban trekking for two months during peak summer.

Question 5.
Always avoid roads and bridge during earthquake.
Answer:
Roads may develop crack and bridges may collapse and damaged by the earthquake so we should be causious.

Question 6.
Cardamom hills are also known as Yelamala.
Answer:
The hill acquires its name from the cardamom spice, which is commonly grown here.

VIII. Answer the following in a paragraph

Question 1.
Write about the location and size of Tamil Nadu.
Answer:
Location: Tamil Nadu is located in the Southern most part of the country. It is one among the 29 states of India.

Extent: Latitudinally this land mass extends from 8°4’N to 13°35’N and longitudinally from 76°18’E to 80°20’E longitudes.

Extremities: Its Eastern and Western extremities are defined by the point calimere and the hills of Anaimalai respectively.

The Northern extremity of the state is Pulicate lake and the Southern most point is Cape Comorin.

Area: It covers an area of 1,30,058 sq.km covering 4% of the area of our country.

Size: It is the 11th largest state.

Question 2.
Tabulate the administrative Divisions of Tamil Nadu.
Answer:
The administrative divisions of the Tamil Nadu state are given under.

Division	Number
Districts	35 (32 + 3)
Revenue Divisions	76
Taluks	226
Firkas (Local Revenue Sub-divisions)	1,127
Revenue villages	16,564
Municipal Corporation	15
Municipalities	125
Panchayat Unions (Blocks)	385
Town Panchayats	561
Village Panchayats	12,618
Lok Sabha Constituencies	39
Assembly Constituencies	234

Question 3.
What are the users of forests?
Answer:
Tamil Nadu’s wealth of flora and fauna lies in the hilly and forest regions.

1. Forests are the sanctuaries for wild animals.
2. It provides valuable forest products like Cinchona, Eucalyptus, which are used as medicine for cold, malaria and as a pain reliever.
3. Palmyrah trees are useful for construction works.
4. Forest products are used as raw materials for several cottage industries.
5. Sandalwood is useful for making furniture.
6. These forests not only provide for the large economy of the state but also to the local livelihood.

Question 4.
Give an account of the River Thamirabarani.
Answer:

1. The name is interpreted as Thamiram (copper) Varuni (streams of river).
2. The water of this river gives a copper like appearance due to the presence of dissolved red soil.
3. The river originates from a peak in Pothigai hills on the Western Ghats above Papanasam in the Ambasamudram taluk, (only river originates in Tamil Nadu).
4. The origin of the river is associated with Sage Agasthiyar.
5. It courses through the districts of Tirunelveli and Thoothukudi.
6. It flows into Bay of Bengal near Punnaikayal in Thoothukudi district.
   Tributaries: Karaiyar, Servalar, Manimuthar, Gadananathi, Pachaiyar, Chittar and Ramanathi.
7. It is the only Perennial river of Tamil Nadu as it is fed by both the Southwest and Northeast monsoons.

Question 5.
Write about Pichavaram mangrove forest.
Answer:

1. Pichavaram mangrove forest is located near Chidambaram, Cuddalore district.
2. This is the second largest mangrove forest in the world covering about 1,100 hectares (11 sq.km) of area.
3. It is separated from the Bay of Bengal by a sandbar.
4. It consists of species like Avicennia and Rhizophora.
5. It also supports the existence of rare varieties of shell and fin fishes.

Question 6.
Name any five wild life (Animal) sanctuaries and Bird Sancturies in Tamil Nadu and their location.
Answer:

S.No	Name of the Wildlife Sanctuary	Location
1.	Mudumalai	Nilgiris
2.	Indira Gandhi	Coimbatore
3.	Sathyamangalam	Erode
4.	Grizzled Giant Squirrel	Virudhunagar
5.	Kalakad	Tirunelveli

S.No	Name of the Bird Sanctuary	Location
1.	Pulicat Lake	Tiruvallur
2.	Kanjirankulam	Ramanathapuram
3.	Vedanthangal	Kancheepuram
4.	Koonthankulam-kadankulam	Tirunelveli
5.	Karaivetti	Ariyalur

Question 7.
Write a paragraph on Tropical cyclonic rainfall in Tamil Nadu.
Answer:

1. Tropical cyclones are common during the North – East monsoon season. (October – December)
2. Cyclone originating from Bay of Bengal bring heavy rainfall to the east coastal regions of Tamil Nadu.
3. More than 50% of the state’s rainfall is received from tropical cyclones during this period amount of rainfall.
4. East coastal regions receive 100 to 200 cms of rainfall.
5. Central and North western parts receives 50 – 100 cm of rainfall.
6. The cyclones some times disturb the cultivation of crops and cause severe damage to life and property.

Question 8.
How Tamil Nadu can be classified in to based on cyclone prone zone? Mention the areas of very high and high zone.
Answer:
Based on the cyclone hit areas that ares often hit by the tropical cyclone formed in Bay of Bengal during Northeast monsoon season. Tamil Nadu is classified into five zones. Namelys

Very high, high, medium, low and veiy low cyclone prone zone.

Areas:
Very high zone: Southern part of Chennai, Eastern part of Kanchipuram and Villupuram, North Eastern part of Cuddalore and Union territory of Puduchery.

High zone: Nagapattinam, Thiruvallur, Tiruvarur (except North Western part) Southern part of Tanjavur, Eastern part of Pudukottai, Cuddalore, Tiruvannamalai, North Eastern part of Vellore, Northern part of Chennai, North Western part to Kanchipuram and Middle portion of Villupuram.

Question 9.
How can we manage water scarcity? Suggest some methods of water conservation.
Answer:

1. Tamil Nadu is water deficit state.
2. To manage water deficit, rain water harvesting and water conservation methods have to be implemented strictly.

Methods of water conservation:

1. Protect water conservation.
2. Rational use of ground water.
3. Renovation of traditional water source.
4. Increasing forest cover.
5. Recycling of water for other uses.
6. Changing crop pattern.
7. Flood management.
8. Use of geo-thermal water.

IX. Map study

Question 1.
On the given map of Tamil Nadu mark the following.
Answer:
(a) (i) Boundaries of Tamil Nadu
(ii) Capital of Tamil Nadu and its District.

Districts: (i) Any two coastal districts on the east
(ii) Kanyakumari, Cape Comorin, Nilgiris, Vellore
(iii) Pulicate lake.

(b)

1. Gulf of Mannar
2. Palk Strait
3. Palk Bay
4. Pamban
5. Rameswaram
6. Coromandel coast
7. Kaveri plains
8. Dharmapuri
9. Kollidam
10. Mettur Dam

(c)

1. Ooty
2. Kodaikanal
3. Doddabetta
4. Mukurti lake
5. Sathuragiri
6. Perumalmalai
7. Palani hills
8. Javadhi hills
9. Elagiri
10. Point calimere
11. Agathiyamalai

Students can download 10th Science Chapter 17 Reproduction in Plants and Animals Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 17 Reproduction in Plants and Animals

Samacheer Kalvi 10th Science Reproduction in Plants and Animals Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
The plant which propagates with the help of its leaves is:
(a) Onion
(b) Neem
(c) Ginger
(d) Bryophyllum
Answer:
(d) Bryophyllum

Question 2.
Asexual reproduction takes place through budding in ______.
(a) Amoeba
(b) Yeast
(c) Plasmodium
(d) Bacteria.
Answer:
(b) Yeast

Question 3.
Syngamy results in the formation of:
(a) Zoospores
(b) Conidia
(c) Zygote
(d) Chlamydospores
Answer:
(c) Zygote

Question 4.
The essential parts of a flower are ______.
(a) Calyx and Corolla
(b) Calyx and Androecium
(c) Corolla and Gynoecium
(d) Androecium and Gynoecium.
Answer:
(d) Androecium and Gynoecium.

Question 5.
Anemophilous flowers have:
(a) Sessile stigma
(b) Small smooth stigma
(c) Colored flower
(d) Large feathery stigma
Answer:
(d) Large feathery stigma

Question 6.
Male gametes in angiosperms are formed by the division of ______.
(a) Generative cell
(b) Vegetative cell
(c) Microspore mother cell
(d) Microspore.
Answer:
(a) Generative cell

Question 7.
What is true of gametes?
(a) They are diploid
(b) They give rise to gonads
(c) They produce hormones
(d) They are formed from gonads
Answer:
(d) They are formed from gonads

Question 8.
A single highly coiled tube where sperms are stored, get concentrated and mature is known as ______.
(a) Epididymis
(b) Vasa efferentia
(c) Vas deferens
(d) Seminiferous tubules.
Answer:
(d) Seminiferous tubules.

Question 9.
The large elongated cells that provide nutrition to developing sperms are:
(a) Primary germ cells
(b) Sertoli cells
(c) Leydig cells
(d) Spermatogonia
Answer:
(b) Sertoli cells

Question 10.
Estrogen is secreted by ______.
(a) Anterior pituitary
(b) Primary follicle
(c) Graafian follicle
(d) Corpus luteum.
Answer:
(b) Primary follicle

Question 11.
Which one of the following is an IUCD?
(a) Copper – T
(b) Oral pills
(c) Diaphragm
(d) Tubectomy
Answer:
(a) Copper – T

II. Fill in the blanks:

1. The embryo sac in a typical dicot at the time of fertilization is ………
2. After fertilization the ovary develops into ………
3. Pianaria reproduces asexuallv by ………
4. Fertilization is ……….. in humans.
5. The implantation of the embryo occurs at about ……….. day of fertilization.
6. ………. is the first secretion from the mammary gland after child birth.
7. Prolactin is a hormone produced by …………

Answer:

1. Double fertilization
2. Fruits
3. Regeneration
4. Internal
5. 6 to 7
6. Colostrum
7. Anterior pituitary

III. Match the following:

Question 1.

Answer:
A. (ii)
B. (iii)
C. (i)

Question 2.
Match the following terms with their respective meanings

Answer:
A. (iii)
B. (i)
C. (iv)
D. (ii)

IV. State whether the following statements are True or False. Correct the false statement.

1. Stalk of the ovule is called pedicle.
2. Seeds are the product of asexual reproduction.
3. Yeast reproduces asexually by means of multiple fission.
4. The part of the pistil which serves as a receptive structure for the pollen is called as style.
5. Insect pollinated flowers are characterized by dry and smooth pollen.
6. Sex organs produce gametes which are diploid.
7. LH is secreted by the posterior pituitary.
8. Menstrual cycle ceases during pregnancy.
9. Surgical methods of contraception prevent gamete formation.
10. The increased level of oestrogen and progesterone is responsible for menstruation.
Answer:
1. False – Stalk of the ovule is called Funiculus
2. False – Seeds are the product of sexual reproduction
3. False – Budding reproduces asexually by means of multiple fission.
4. False – The part of the pistil which serves as a receptive structure or the pollen is called as stigma.
5. False – Wind pollinated flowers are characterized by dry and smooth pollen.
6. False – Sex organs produce gametes which are haploid
7. False – Anterior pituitary (LH is secreted by the Anterior pituitary)
8. True
9. True
10. True

V. Answer in a word or sentence.

Question 1.
If one pollen grain produces two male gametes, how many pollen grains are needed to fertilize 10 ovules?
Answer:
Atleast 10 pollen grains required to fertilise 10 ovules because only one male gamete is involved in the fusion of male gamete with the egg cell.

Question 2.
In which part of the flower germination of pollen grains takes place?
Answer:
Pollen grains reach the stigma and begin to germinate.

Question 3.
Name two organisms which reproduces through budding.
Answer:
Yeast and hydra reproduce through budding.

Question 4.
Mention the function of the endosperm.
Answer:
The endosperm provides food to the developing embryo.

Question 5.
Name the hormone responsible for the vigorous contractions of the uterine muscles.
Answer:
Oxytocin from the posterior pituitary stimulates the uterine contraction.

Question 6.
What is the enzyme present in the acrosome of sperm?
Answer:
Hyaluronidase is the enzyme, present in the acrosome of sperm, which helps the sperm to enter the ovum during fertilization.

Question 7.
When is World Menstrual Hygiene Day observed?
Answer:
Every year May 28th is observed as Menstrual Hygiene day to make girls and women aware of maintaining menstrual hygiene and importance of menstrual hygiene for good health.

Question 8.
What is the need for contraception?
Answer:
Contraception is used to prevent pregnancy, to check population growth.

Question 9.
Name the part of the human female reproductive system where the following occurs, (a) Fertilization (b) Implantation
Answer:
(a) Fertilization: Occurs in the oviduct of the female genital tract. It takes place usually in the ampulla of the fallopian tube.
(b) Implantation: Blastocyst reaches the uterus (uterine wall) (endometrium)

VI. Short Answer Questions

Question 1.
What will happen if you cut planaria into small fragments?
Answer:
Each fragment will develop into a new individual by a specialized mass of cell. It is called regeneration. It is the ability of the lost body parts of an individual organism to give rise to a whole new organism.

Question 2.
Why is vegetative propagation practised for growing some type of plants?
Answer:
The vegetative part of plant, root, stem, leaf or budgets detached from the parent body and grows into an independent daughter plant by mitotic division. The daughter plants are genetically similar to the parent plant.

Question 3.
How does binary fission differ from multiple fission?
Answer:

Question 4.
Define triple fusion.
Answer:
The fusion involving two polar nuclei and a sperm nucleus, that occurs in double fertilization in a seed plant and results in the formation of endosperm, is called the triple fusion.

Question 5.
Write the characteristics of insect-pollinated flowers.
Answer:

1. The flowers are brightly coloured to attract insects which have smell and nectar.
2. The pollen grains are larger in size, the exine is pitted, spiny, so they can be adhered firmly on the stucky stigma.

Question 6.
Name the secondary sex organs in male.
Answer:
The secondary sex organs in the male are vas deferens, Epididymis, seminal vesicle, prostate gland and penis.

Question 7.
What is colostrum? How is milk production hormonally regulated?
Answer:
The milk produced from the breast during the first 2 to 3 days after child birth is called colostrum. Milk production from alveoli of mammary glands is stimulated by prolactin secreted from the anterior pituitary.

Question 8.
How can menstrual hygiene be maintained during menstrual days?
Answer:
Maintaining menstrual hygiene is important for the overall health of women.

• Sanitary pads should be changed regularly, to avoid infections due to microbes from vagina and sweat from genitals.
• Use of warm water to clean genitals, to get rid of menstrual cramps.
• Wearing loose clothing, to ensure the airflow around the genitals, to prevent sweating.

Question 9.
How does developing embryo gets its nourishment inside the mother’s body?
Answer:
The developing embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. It is embedded in the uterine wall. This is a disc like tissue which develops between the uterine walls and embryo. It has villi of embryo side of the tissue. On the mother side are blood spaces with the villi. This gives a large surface area for oxygen and glucose to pass from the mother to the embryo.

Question 10.
Identify the parts A, B, C and D.

Answer:
A – Exine
B – Intine
C – Generative nucleus
D – Vegetative nucleus

Question 11.
Write the events involved in the sexual reproduction of a flowering plant.

1. Discuss the first event and write the types.
2. Mention the advantages and disadvantages of that event.

Answer:

1. The transfer of pollen grains from the anther to the stigma of a flower is called pollination. Self – Pollination and Cross-Pollination are the two types of Pollination.
2. Advantages:
   • It results in fertilization, which leads to the formation of fruits and seeds.
   • New varieties of plants are formed, through a new combination of genes,
3. Disadvantages:
   • More wastage of pollen grains.
   • Pollination may fail due to the distance barrier.
   • Flowers depend on external agencies for pollination.

Question 12.
Why are the human testes located outside the abdominal cavity? Name the pouch in which they are present.
Answer:
Human testes responsible for synthesis of male gametes(sperms) need slightly lower temperature than the normal body temperature for this function. Thus, they are located outside the abdominal cavity in a sac like structure called scrotum.

Question 13.
The luteal phase of the menstrual cycle is also called the secretory phase. Give reason.
Answer:
During the Luteal phase of the menstrual cycle in the uterus, the hormone progesterone is produced by the ovaries. Progesterone and estrogen are secreted by the Corpus Luteum, which develops from the Graafian follicle. So this phase of the menstrual cycle is called the secretory phase.

Question 14.
Why are family planning methods not adopted by all the people of our country?
Answer:
Family planning is a way of living that is adopted voluntary by couples on the basis of knowledge and responsible decision to promote the health and welfare of the family group and society. As it is voluntary many people are not aware of the importance of family planning.

VII. Long Answer Questions.

Question 1.
With a neat labelled diagram describe the parts of a typical angiospermic ovule.
Answer:
Structure of the Ovule : The main part of the ovule is the nucellus which is enclosed by two integuments leaving an opening called as micropyle. The ovule is attached to the ovary wall by a stalk known as funiculus. Chalaza is the basal part.

The embryo sac contains seven cells and the eighth nuclei located within thenucellus. Three cells at the micropylar end form the egg apparatus and the three cells at the chalaza end are the antipodal cells. The remaining two nuclei are called polar nuclei found in the centre. In the egg apparatus one is the egg cell (female gamete) and the remaining two cells are the synergids.

Question 2.
What are the phases of menstrual cycle? Indicate the changes in the ovary and uterus.
Answer:

VIII. Higher Order Thinking Skills: (HOTS)

Question 1.
In angiosperms, the pollen germinates to produce a pollen tube that carries two gametes. What is the purpose of carrying two gametes when single gamete can fertilize the egg?
Answer:
One sperm fuses with the egg (syngamy) and forms a diploid zygote. The other sperm fuses with the secondary nucleus (Triple fusion) to form the primary endosperm. After triple fusion, the primary endosperm nucleus develops into an endosperm. The purpose of carrying two gametes is, endosperm provides food to the developing embryo.

Question 2.
Why menstrual cycle does not take place before puberty and during pregnancy?
Answer:
Menstruation occur when the egg is not fertilized. Every month uterus prepares itself to receive the fertilized egg to nourish the embryo, its lining becomes thick and spongy for implantation of the fertilized egg.
In case egg is not fertilized thin lining breaks and discharged out of the body through the vagina in the form of blood.
This condition will not happen before puberty and during pregnancy.

Question 3.
Read the following passage and answer the questions that follow:
Rohini and her parents were watching a television programme. An advertisement flashed on the screen which was promoting the use of sanitary napkins. Rohini’s parents suddenly changed the channel, but she objected to her parents and explained the need and importance of such advertisement.
(a) What is first menstruation called? When does it occur?
(b) List out the napkin hygiene measures taken during menstruation?
(c) Do you think that Rohini’s objection towards her parents was correct? If so, Why?
Answer:
(a) The first period or menstruation is a point in time, known as Menarche. It usually begins between 12 to 15 years of age.

(b)

1. The sanitary pad and tampons should be wrapped properly and discarded because they can spread infections.
2. Sanitary pad or tampon should not be flushed down the toilet.
3. Napkin incinerators are to be used properly for disposal of used Napkins.

(c) No, it was not correct. The parents and teachers have to create awareness among the school girls about the use of Napkins and their proper disposal. Girls should be educated and should know the importance of such advertisement on Television.

Samacheer Kalvi 10th Science Reproduction in Plants and Animals Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
In a pollen grain the small nucleus is:
(a) Generative nucleus
(b) Tube nucleus
(c) Vegetative nucleus
(d) Pollen nucleus
Answer:
(a) Generative nucleus

Question 2.
The female part of the flower is ______.
(a) Androecium
(b) Anemophily
(c) Gynoecium
(d) Micropyle.
Answer:
(c) Gynoecium

Question 3.
Spirogyra is an:
(a) Virus
(b) Fungi
(c) Bacteria
(d) Algae
Answer:
(d) Algae

Question 4.
During pregnancy, the uterus expands, it’s normal size up to ______.
(a) 200 times
(b) 500 times
(c) 600 times
(d) 800 times.
Answer:
(b) 500 times

Question 5.
In wind pollinated flowers, the pollen grains are:
(a) sticky and powdery
(b) small and powdery
(c) dry and powdery
(d) wet and powdery
Answer:
(c) dry and powdery

Question 6.
Androecium is the part of the flower.
(a) upper
(b) male
(c) lower
(d) female
Answer:
(b) male

Question 7.
Zygote is a resulting product of:
(a) Germination
(b) Pollination
(c) Fusion of Embryosac
(d) Fertilization
Answer:
(d) Fertilization

Question 8.
Pick out the correct statement:
(a) Endosperm is a connective tissue
(b) Endosperm is a muscular tissue
(c) Endosperm is a nutritive tissue
(d) Endosperm is a nervous tissue
Answer:
(c) Endosperm is a nutritive tissue

Question 9.
The follicle that ruptures at the time of ovulation promptly fills with blood, forming:
(a) Corpus Luteum
(b) Corpus albricans
(c) Corpus Collosum
(d) Corpus Haemorrhagueim
Answer:
(a) Corpus Luteum

Question 10.
The endometrium is the lining of:
(a) bladder
(b) vagina
(c) uterus
(d) oviduct
Answer:
(c) uterus

Question 11.
Menstrual flow occurs due to lack of:
(a) Progesterone
(b) FSH
(c) Oxytocin
(d) Vasopressin
Answer:
(a) Progesterone

Question 12.
Testosterone is secreted by:
(a) Leydig cells
(b) Sertoli cells
(c) Seminiferous tubule
(d) None of these
Answer:
(d) None of these

Question 13.
In mammals, maturation of sperms take place at a temperature:
(a) Equal to that of body
(b) Higher than that of body
(c) Lower than that of body
(d) At any piece of mammalian sperm
Answer:
(c) Lower than that of body

Question 14.
If menstrual cycle is 30 days and bleeding starts on 1st day, then ovulation occur on:
(a) 14th day
(b) 18th day
(c) 30th day
(d) 16th day
Answer:
(d) 16th day

Question 15.
The symbol of family planning in India is:
(a) Square
(b) Inverted red triangle
(c) Rectangle
(d) Circle
Answer:
(b) Inverted red triangle

II. Fill in the blanks.

1. Purpose of tubectomy is to prevent ………
2. Progesterone is secreted by ………..
3. Sertoli cells are found mg in ………….
4. Hormone responsible for ovulation and development of corpus luteum is ………..
5. First menstrual cycle starts is ………..
6. The functional maturation of sperms takes place in ………..
7. Seeds develops from …………
8. In ……… buds are produced in the notches along the leaf margin.
9. Androecium is a group of …………
10. In self pollination, flowers need not to depend on ………… of pollination.
11. Pollination by wind is called ………..
12. The point of attachment of ovule to the funicle is known as …………..
13. In Angiosperm pollen tube liberate their male gametes into the …………
14. Double fertiliztaion is essential for formation of ……….
15. During spore formation a structure called ………… develops from the fungal hypha
Answer:
1. Fertilization
2. Corpus luteum
3. Seminiferous tubule
4. LH
5. Menarche
6. Epididyms
7. Ovule
8. Bryophyllum
9. Stamens
10. Agents
11. Anemophily
12. Hilum
13. Synergids
14. Endosperm
15. Sporangium

III. Match the following

Question 1.
Match the Column I with Column II.

Answer:
A. (v)
B. (i)
C. (ii)
D. (iii)
E. (iv)

Question 2.
Match the Column I with Column II

Answer:
A. (ii)
B. (i)
C. (iv)
D. (v)
E. (iii)

IV. Assertion and Reasoning:

Direction: In each of the following questions a statement of assertion (A) is given and a corresponding statement of reason (R) is given just below it. Mark the correct statement as.
Question 1.
Assertion (A): Some of the Angiospermic plants are propagated only by vegetative propagation.
Reason (R): They have lost the capacity of seed formation.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(a) If both A and R are true and R is correct explanation of A.

Question 2.
Assertion (A): Double fertilization is the universal features of all plants.
Reason (R): In this fusion only male gametes and secondary nucleus takes place.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(d) Both A and R are false.

Question 3.
Assertion (A): The unit of Androecium is called stamen.
Reason (R): The most important part of androecium is anther.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(c) A is true but R is false.

Question 4.
Assertion (A): Anemophily includes wastage of pollen grains.
Reason (R): Anemophilous flowers are neither attractive nor fragrant.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(b) If both A and R are true but R is not the correct explanation of A.

Question 5.
Assertion (A): Sexual reproduction takes place with the participation of two different type of gametes.
Reason (R): Sexual reproduction is also known as Apomixies.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(c) A is true but R is false.

Question 6.
Assertion (A): In India, IUDS most widely accepted methods of contraception.
Reason (R): IUDS are injectable contraceptives, which prevent pregnancy for three months.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(c) A is true but R is false.

Question 7.
Assertion (A): Over population has become a serious problem in developing countries.
Reason (R): It may exhaust natural resources, cause unemployment and lead to pollution.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer:
(a) If both A and R are true and R is correct explanation of A.

V. State whether True or false, If false write the correct statement

1. Tubectomy a method of population control performed on males.
2. Oral pills are very popular contraceptives among the rural women.
3. The germ pore of dicot seed is known as micropyle.
4. Vegetative reproduction is a kind of asexual reproduction.
5. The protective wall of the pollen is intine.

Answer:

1. False – Tubectomy a method of population control performed on females
2. False – Oral pills are very popular contraceptives among the urban women
3. True
4. True
5. False – The protective wall of the pollen is exine.

VI. Answer in a word or sentence:

Question 1.
Define reproduction.
Answer:
Reproduction is the process of producing offspring of their own kind.

Question 2.
Define Fertilization.
Answer:
The fusion of male gamete with female gamete to form zygote is called fertilization.

Question 3.
Where the fertilization takes place in human female?
Answer:
Fertilization in human female occurs in the oviduct of the female genetal tract. It takes place usually in the ampulla of the fallopian tube.

Question 4.
Name two types of reproduction.
Answer:
Asexual and Sexual reproduction.

Question 5.
Define Menstruation.
Answer:
Menstruation is a periodical phenomenon that continues from puberty to menopause. This will happen if the released ovum is not fertilized by the sperm.

Question 6.
Write the name of male and female reproductive part of a flower.
Answer:
Androecium and Gynoecium.

Question 7.
Define gestation period.
Answer:
Gestation is the time period during which the embryo attains its development in the uterus.

Question 8.
What is the gestation period in human?
Answer:
Normally gestation period of human last for about 280 days.

Question 9.
Write the full form of IUD and AIDS.
Answer:
IUD – Intra Uterine devices
AIDS – Acquired Immuno Deficiency Syndrome

Question 10.
What is Menopause?
Answer:
A natural decline in reproductive hormones when a woman reaches 48-50 years of age.

Question 11.
Define Pollination.
Answer:
The transfer of pollen grains from anther to stigma of a flower is called pollination.

Question 12.
What are the agents of pollination?
Answer:
Animals, Insects, Wind and Water are the agents of Pollination.

Question 13.
What is Parturition?
Answer:
Parturition is the expulsion of young one from the mother uterus at the end of gestation.

Question 14.
What is endometrium?
Answer:
The endometrium is the inner epithelial layer along with its mucous membrane of the mammalian uterus.

Question 15.
What are gonads?
Answer:
Organs of the reproductive system are gonads. Testes are male gonads and ovaries are female gonads.

Question 16.
Name two sexually transmitted disease.
Answer:
Syphilis. AIDS

Question 17.
What is Vitelline membrane?
Answer:
The membrane forming the surface layer of the ovum is called vitelline membrane.

Question 18.
Which parts of the flower transform into the seed and fruit?
Answer:
Ovule develops into seed.
Ovary develops into fruit.

Question 19.
Name two sex hormones.
Answer:
Testosterone and Progesterone

Question 20.
What is umblical cord?
Answer:
A cord containing blood vessels that connects the placenta with the foetus is called the umblical cord.

VII. Short Answer Questions

Question 1.
What is vegetative reproduction? Give an example.
Answer:
New plantlets, which are formed from the vegetative (somatic) parts of plants, such as root, stem, leaf or bud from the parent body is called vegetative reproduction, eg. In Bryophyllum, small plants grow at the leaf notches.

Question 2.
What happens when the egg is not fertilized?
Answer:
If the egg is not fertilized, corpus luteum degenerates, the egg disintegrates and the uterine lining slowly breaks, discharges as blood and mucus leading to menstrual events.

Question 3.
Explain the types of Urinary Tract Infection?
Answer:
Woman are susceptible to Urinary Tract Infection from the bacteria, that are present on skin, rectum or vagina. The types of UTI are:

• Cystitis or Bladder infection: Bacteria lodged in the urinary bladder, thrive and multiply leading to inflammation, at the age group of 20 to 50.
• Kidney Infection: The bacteria travels from the urinary bladder and upward to ureter and affect one or both the kidneys. It also infects the bloodstream and leads to serious life-threatening complications.
• Asymptomatic Bacteriuria: The bacteria present in the urinary bladder, which may not show any symptoms.

Question 4.
How does reproduction help in providing stability to population of species?
Answer:
Reproductive ensures the continuity and survival of the species. This process is to preserve individual species and it is called self perpetuation.

Question 5.
What is vegetative propagation? Write two examples where it is used.
Answer:
In vegetative propagation, new plantlets are formed from vegetative cells, buds or organs of plant. The vegetative part of plant get detached from the parent body and grow into an independent daughter plant. Root – Sweet potato, Stem – Strawberry.

Question 6.
What could be the reasons for adopting contraceptive methods?
Answer:

1. To avoid frequent pregnancies, which in turn helps in population control.
2. To prevent the spread of sexually transmitted diseases.

Question 7.
State in brief the function of the following organ,
(a) Ovary
(b) Fallopian tube
Answer:
(a) Ovary – Produce Oocytes (egg) for fertilization and produce hormones – Oestrogen and Progesterone.
(b) Fallopian tube – Transport the egg from the ovary to uterus.

Question 8.
Surgical methods can be used to create a block in the reproductive system for contraceptive purpose. Name such parts where block are created in
(i) Male
(ii) Female.
Answer:
(i) Male – Vasectomy – ligation of vas deferens
(ii) Female – Tubectomy – ligation of Fallopian tube

VIII. Long Answer Questions

Question 1.
List out the different methods of contraceptive. Explain any two.
Answer:
Common contraceptive methods used to prevent pregnancy are:
(i) Barrier methods
(ii) Hormonal methods
(iii) Intra-Uterine Devices (IUDs)
(iv) Surgical methods

(i) Barrier Methods : This method prevents sperms from meeting the ovum. Its entry into the female reproductive tract is prevented by barrier.

1. Condom : Condom prevents deposition of sperms in the vagina. Condoms are made of thin rubber or latex sheath. Condom also protect against sexually transmitted diseases (STD) like syphilis, AIDS.
2. Diaphragm (Cervical cap) : Vaginal diaphragm fitting into the vagina or a cervical cap fitting over the cervix. This prevents the entry of sperms into the uterus.

(ii) Hormonal Methods : Hormonal preparations are in the form of pills or tablets (contraceptive pills). These hormones stop (interfere with ovulation) the release of egg from the ovary.

Question 2.
Explain the structure of pollen grain with a labelled diagram.
Answer:
Pollen grains are usually spherical in shape. It has two layered wall. The hard outer layer is known as exine. It has prominent apertures called germpore. The inner thin layer is known as intine. It is a thin and continuous layer made up of cellulose and pectin. Mature pollen grains contain two cells, the vegetative and the generative cell. Vegetative cell contains a large nucleus. The generative cell divides mitotically to form two male gametes.

Question 3.
Write the advantages and disadvantages of self and cross pollination.
Answer:
Advantages of self-pollination:

1. Self-pollination is possible in certain bisexual flowers.
2. Flowers do not depend on agents for pollination.
3. There is no wastage of pollen grains.

Disadvantages of self-pollination:

1. The seeds are less in numbers.
2. The endosperm is minute. Therefore, the seeds produce weak plants.
3. New varieties of plants cannot be produced.

Advantages of cross pollination:

1. The seeds produced as a result of cross pollination, develop and germinate properly and grow into better plants, i.e., cross pollination leads to the production of new varieties.
2. More viable seeds are produced.

Disadvantages of cross-pollination:

1. Pollination may fail due to distance barrier.
2. More wastage of pollen grains.
3. It may introduce some unwanted characters.
4. Flowers depend on the external agencies for pollination.

Question 4.
Explain the structure of human sperm with diagram.
Answer:

Structure of Human Sperm: The spermatozoan consists of head, a middle piece and tail. The sperm head is elongated and formed by the condensation of nucleus. The anterior portion has a cap like structure called acrosome. It contains hyaluronidase an enzyme that helps the sperm to enter the ovum during fertilization. A short neck connects the head and middle piece which comprises the centrioles. The middle piece contains the mitochondria which provides energy for the movement of tail. It brings about sperm motility which is essential for fertilization.

Question 5.
Explain the structure of ovum with diagram.
Answer:
The mature ovum or egg is spherical in shape. The ovum is almost free of yolk. It contains abundant cytoplasm and the nucleus. The ovum is surrounded by three membranes. The plasma membrane is surrounded by inner thin zona pellucida and an outer thick corona radiata. The corona radiata is formed of follicle cells. The membrane forming the surface layer of the ovum is called vitelline membrane. The fluid-filled space between zona pellucida and the surface of the egg is called perivitelline space.

IX. Give Reason:

Question 1.
If a women is using copper – T, will it help in protecting her from sexual transmitted diseases?
Answer:
No, Copper-T does not prevent the transmission of sexually transmitted diseases. Copper-T only prevents implantation. The only safe method used to prevent the transmission of sexually transmitted diseases is the use of condoms.

Question 2.
Leaves of the Bryophyllum fallen on the ground produce new plants whereas the leaves of rose do not. Why?
Answer:
The leaves of Bryophyllum is levoad and fleshy, has notches at its margins. Buds arise from the notches, but in rose plant notches are absent.

Question 3.
The organisms formed by asexual reproduction are considered as clones. Why?
Answer:
Offspring produced by a asexual reproduction are not only identical to parents, but are also exact copies of their parent because it involves only miotic cell division.

X. Higher Order Thinking Skills (HOTS)

Question 1.
Organism A needs water to multiply and organism B needs sugar solution to multiply. Identify the organism A and B and their method of Reproduction.
Answer:
Organism A is Amoeba – which multiplies by binary fusion.
Organism B is Yeast – which needs sugar medium for budding.

Question 2.
If ovaries from a pregnant woman arc removed in 4th month of pregnancy. What will happen?
Answer:
Embryo develops normally till birth as it grows in the utreus.

Question 3.
A pregnant female not able to delivers the baby due to lack of ‘X’ hormones. Identify ‘X’ hormone. Write its function.
Answer:
The ‘X” hormone is oxytocin. It provides force to expel the baby from the uterus causing birth.

Students can download 10th Science Chapter 15 Nervous System Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 15 Nervous System

Samacheer Kalvi 10th Science Nervous System Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
Bipolar neurons are found in:
(a) retina of eye
(b) cerebral cortex
(c) embryo
(d) respiratory epithelium
Answer:
(a) retina of eye

Question 2.
The site for processing of vision, hearing, memory, speech, intelligence, and thought is ______
(a) kidney
(b) ear
(c) brain
(d) lungs
Answer:
(c) brain

Question 3.
In reflex action, the reflex arc is formed by:
(a) brain, spinal cord, muscle
(b) receptor, muscle, spinal cord
(c) muscle, receptor, brain
(d) receptor, spinal cord, muscle
Answer:
(d) receptor, spinal cord, muscle

Question 4.
Dendrites transmit impulse ______ cell body and axon transmit impulse ______ cell body.
(a) away from, away from
(b) towards, away from
(c) towards, towards
(d) away from, towards
Answer:
(b) towards, away from

Question 5.
The outer most of the three cranial meninges is:
(a) arachnoid membrane
(b) piamater
(c) duramater
(d) myelin sheath
Answer:
(c) duramater

Question 6.
There are …….. pairs of cranial nerves and ………. pairs of spinal nerves.
(a) 12, 31
(b) 31, 12
(c) 12, 13
(d) 12, 21
Answer:
(a) 12, 31

Question 7.
The neurons which carries impulse from the central nervous system to the muscle fibre _____
(a) afferent neurons
(b) association neuron
(c) efferent neuron
(d) unipolar neuron
Answer:
(c) efferent neuron

Question 8.
Which nervous band connects the two cerebral hemispheres of brain?
(a) thalamus
(b) hypothalamus
(c) corpus callosum
(d) pons
Answer:
(c) corpus callosum

Question 9.
Node of Ranvler is found in:
(a) muscles
(b) axons
(c) dendrites
(d) cyton
Answer:
(b) axons

Question 10.
Vomiting centre is located in ______
(a) medulla oblongata
(b) stomach
(c) cerebrum
(d) hypothalamus
Answer:
(a) medulla oblongata

Question 11.
Nerve cells do not possess:
(a) neurilemma
(b) sareolemma
(c) axon
(d) dendrites
Answer:
(b) sareolemma

Question 12.
A person who met with an accident lost control of body temperature, water balance, and hunger. Which of the following part of the brain is supposed to be damaged?
(a) medulla oblongata
(b) cerebrum
(c) pons
(d) hypothalamus
Answer:
(d) hypothalamus

II. Fill in the blanks:

1. ……….. is the longest cell in our body.
2. Impulses travels rapidly ……….. in ……….. neurons.
3. A change in the environment that causes an animal to react is called ………..
4. ………. carries the impulse towards the cell body.
5. The two antagonistic component of autonomic nervous system are ……….. and ……….
6. A neuron contains all cell organelles except …………
7. ………. maintains the constant pressure inside the cranium.
8. ………… and ………… increases the surface area of cerebrum.
9. The part of human brain which acts as relay center is ………….

Answer:

1. Nerve cell or neuron
2. sensory
3. stimulus
4. Dentrites
5. sympathetic and parasympathetic system
6. Nucleus
7. Cerebro Spinal Fluid (CSF)
8. Gyri and sulci
9. thalamus

III. State whether true or false, if false write the correct statement:

1. Dendrons are the longest fibres that conducts impulses away from the cell body.
2. Sympathetic nervous system is a part of central nervous system.
3. Hypothalamus is the thermoregulatory centre of human body.
4. Cerebrum controls the voluntary actions of our body.
5. In the central nervous system myelinated fibres form the white matter.
6. All the nerves in the body are covered and protected by meninges.
7. Cerebrospinal fluid provides nutrition to brain.
8. Reflex arc allows the rapid response of the body to a stimulus.
9. Pons helps in regulating respiration.

Answer:

1. False – Axons are the longest fibres that conducts impulses away from the cell body.
2. False – Autonomic nervous system is a part of central nervous system.
3. True
4. False – Cerebellum controls the voluntary actions of our body.
5. True
6. False – Brain is covered and protected by meninges.
7. True
8. True
9. True

IV. Match the following:

Answer:
A. (iii)
B. (i)
C. (iv)
D. (ii)

V. Understand the assertion statement. Justify the reason given and choose the correct choice:

(a) Assertion is correct and reason is wrong.
(b) Reason is correct and the assertion is wrong.
(c) Both assertion and reason are correct.
(d) Both assertion and reason are wrong.
1. Assertion: Cerebrospinal fluid is present throughout the central nervous system.
Reason: Cerebrospinal fluid has no such functions.
Answer:
(a) Assertion is correct and reason is wrong.

2. Assertion: Corpus callosum is present in space between the duramater and . piamater.
Reason: It serves to maintain the constant intracranial pressure.
Answer:
(d) Both assertion and reason are wrong.

VI. Short Answer Questions:

Question 1.
Define the stimulus.
Answer:
The changes in the environmental condition that are detected by the receptors present in the body is called stimulus.

Question 2.
Name the parts of the hindbrain.
Answer:
The hindbrain is formed of three parts. Cerebellum, Pons and Medulla Oblongata.

Question 3.
What are the structures involved in the protection of brain?
Answer:
Cranium (skull) and three connective tissue membrane meninges – Duramater, Arachnoid membrane and piamater protect the brain.

Question 4.
Give an example for conditioned reflexes.
Answer:
The conditioned reflexes are the result of practice and learning. Playing the harmonium by striking a particular key, on seeing a music note is an example of conditioned reflexes.

Question 5.
Which acts as a link between the nervous system and endocrine system?
Answer:
Hypothalamus is the link between nervous system and endocrine system as it controls the secretion of hormones from anterior pituitary gland.

Question 6.
Define reflex arc.
Answer:
The path taken by nerve impulse to accomplish reflex action is called a Reflex arc.

VII. Differentiate between:

Question 1.
Voluntary and involuntary actions.
Answer:

Question 2.
Medullated and non-medullated nerve fibre.
Answer:

VIII. Long Answer Questions:

Question 1.
Illustrate the structure and functions of brain.
Answer:
The human brain is divided into 3 major parts. Fore brain, Mid brain and Hind brain.
Fore brian consists of Cerebrum, Thalamus and Hypothalamus.

Mid brain
Parts of the brain is Corpora quadrigemina
Function is control visual and auditory reflexes.

Hind brain consists of Pons, Cerebellum and Medulla Oblongata.

Question 2.
What will you do if someone pricks your hand with a needle? Elucidate the pathway of response with a neat labelled diagram.
Answer:
If we touch a sharp pointed object, we immediately withdraw our hand.
Here the skin is the receptor and it receives the stimulus, that is the pain. This stimulus (pain) in turn triggers an impulse in sensory neuron. The sensory neuron transmits or convey the message to the spinal cord. Spinal cord interprets the stimulus and the impulse is passed on to the relay neuron which in turn transmits it to a motor neuron. Motor neuron carry command from the spinal cord to our arm. Muscle in our arm contracts and we withdraw our hand immediately

Question 3.
With a neat labelled diagram explain the structure of a neuron.
Answer:

A neuron is the basic structural and functional unit of the nervous system. A neuron consists of Cyton, Dendrites and Axon.
Cyton : It has a central nucleus with abundant cytoplasm called neuroplasm. The cytoplasm has large granular body called Nissl’s granules and the other cell organelles like mitochondria, ribosomes, lysosomes, and endoplasmic recticulum.

Dendrites : These are the numerous branched cytoplasmic processes that project from the surface of the cell body. They conduct nerve impulses towards the cyton.

Axon : The axon is a single, elongated, slender projection. The end of axon terminates as fine branches which terminate into knob like swellings called synaptic knob. The plasma membrane of axon is called axolemma, while the cytoplasm is called axoplasm. It carries impulses away from the cyton. The axons may be covered by a protective sheath called myelin sheath which is further covered by a layer of Schwann ceils called neurilemma. Myelin sheath breaks at intervals by depressions called Nodes of Ranvier. The region between the nodes is called as internode. Myelin sheath acts as insulator and ensures rapid transmission of nerve impulses.

Question 4.
Describe the structure of spinal cord.
Answer:
Spinal cord is a cylindrical structure lying in the neural canal of the vertebral column. It is also covered by meninges.
It extends from the lower end of medulla oblongata to the first lumbar vertebra. The posterior most region of spinal cord tapers into a thin fibrous thread like structure called filum terminale.

Internally, the spinal cord contains a cerebrospinal fluid filled cavity known as the central canal. The grey matter of spinal cord is ‘H’ shaped. The upper end of letter ‘H” forms posterior horns and lower end forms anterior horns. A bundle of fibres pass into the posterior horn forming dorsal or afferent root. Fibres pass outward from the anterior hom forming ventral or efferent root. These two roots joins to form spinal nerves. The white matter is external and have bundle of nerve tracts. Spinal cord conducts sensory and motor impulses to and from the brain. It controls reflex actions of the body.

Question 5.
How nerve impulses are transferred from one neuron to next neuron?
Answer:
The information from the environment are detected by the receptors located in our sense organs such as the eyes, the nose, the skin etc..
Information from the receptors is transmitted as electrical impulse and is received by the dendritic tips of the neuron.
This impulse travels from the dendrite to the cell body and then along the axon to its terminal end.

On reaching the axonal end, it causes the nerve endings to release a chemical (neuro transmitter) which diffuses across a synapse and starts a similar electrical impulse in the dendrites of the next neuron, then to their cell body to be carried along the axon.

In this way, the electrical signal reaches the brain or spinal cord. The response from brain (or spinal cord) is similarly passed on to the effector organs such as the muscle or gland cell, that undergoes the desired response.

The flow of nerve impulses from axonal end of one neuron to dendrite of another neuron through a synapse is called synaptic transmission.

Question 6.
Classify neurons based on its structure.
Answer:
The neurons may be of different types based on their structure and functions. Structurally the neurons may be of the following types:

(i) Unipolar neurons: Only one nerve process arises from the cyton which acts as both axon and dendron.
(ii) Bipolar neurons: The cyton gives rise to two nerve processes of which one acts as an axon while another as a dendron.
(iii) Multipolar neurons: The cyton gives rise to many dendrons and an axon.

IX. Higher Order Thinking Skills: (HOTS)

Question 1.
‘A’ is a cylindrical structure that begins from the lower end of the medulla and extends downwards. It is enclosed in bony cage 4B’ and covered by membranes ‘C’. As many as ‘D’ pairs of nerves arise from the structure ‘A’.
(i) What is A?
(ii) Name (a) bony cage ‘B’ and (b) membranes ‘C’
(iii) How much is D?
Answer:
(i) Spinal cord
(ii) (a) Cranium
(b) Duramater, Arachnoid membrane, Piamater
(iii) 31 pairs of Spinal nerves

Question 2.
Our body contains a large number of cells ‘L’ which are the longest cells in the body.
L has long and short branch called as ‘M’ and ‘N’ respectively. There is a gap ‘O’ between two ‘l’ cells, through which nerve impulse transfer by release of chemical substance ‘P’.

1. Name the cells L.
2. what are M and N?
3. What is the gap O?
4. Name the chemical substance P.

Answer:

1. L is Nerve cell or Neuron
2. M is axon and N is dendrite
3. Gap O is synaptic junction
4. P is neuro transmitter – Acetylcholine

Samacheer Kalvi 10th Science Nervous System Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
Inner layer of Axon is:
(a) Myelin sheath
(b) Neurilemma
(c) Meninges
(d) Sarcolemma
Answer:
(b) Neurilemma

Question 2.
Which one is thin and vascularised?
(a) Piamater
(b) Duramater
(c) Arachnoid membrane
(d) Pleural membrane
Answer:
(b) Duramater

Question 3.
Uni polar neurons are found in:
(a) Adult nervous tissue
(b) Stem cells
(c) Embryonic stem cells
(d) Embryonic nervous tissue
Answer:
(d) Embryonic nervous tissue

Question 4.
Among the following which one controls our anger.
(a) Hypothalamus
(b) Cerebrum
(c) Cerebellum
(d) Thalamus
Answer:
(a) Hypothalamus

Question 5.
………. form the cerebral cortex of our brain.
(a) Grey neuron
(b) Fibrous tissue
(c) White neurons
(d) Ganglions
Answer:
(c) White neurons

Question 6.
……… is fitted with neuro transmitter.
(a) Synaptic knob
(b) Synaptic plate
(c) Synaptic cleft
(d) Synaptic branch
Answer:
(a) Synaptic knob

Question 7.
The functional connection between two neurons is called:
(a) Synapse
(b) Synapsis
(c) Chiasma
(d) Chiasmata
Answer:
(a) Synapse

Question 8.
Which of the following pair is correct?
(a) Sensory nerve – afferent
(b) Motor nerve – afferent
(c) Sensory nerve – ventral
(d) Motor nerve-dorsal
Answer:
(a) Sensory nerve – afferent

Question 9.
A healthy person got injured resulting in damage and death of a few cells. Which of the cells are least likely to be replaced by new cells:
(a) Liver cell
(b) Neuron
(c) Nephron
(d) Osteocytes
Answer:
(b) Neuron

Question 10.
The number of pairs of spinal nerves in human being is:
(a) 12
(b) 18
(c) 31
(d) 24
Answer:
(c) 31

II. Fill in the blanks:

1. ………lies at the base of the thalamus.
2. ………. transmit electrical impulses towards the cyton.
3. The sensory organs contain ………. neuron.
4. Mid brain with ………. together form the brain stems.
5. Chemical substances which take part in synaptic transmission is ……….
6. The membrane which cover the brain and the spinal cord is ………..
7. If the corpus collosum is removed in Mammalian brain then ……… will be affected.
8. Last end of spinal cord is called ………..
9. The …………. is the continuation of medulla oblongata.
10. ………. is the part of the brain which helps to maintain balance.
Answer:
1. Hypothalamus
2. Dendrites
3. Bypolar
4. Hind brain
5. acetycholine
6. Meninges
7. coordination of cerebrum
8. filum terminate
9. spinal cord
10. Cerebellum

III. State whether true or false, if false write the correct statement.

1. The gaps on the cyton are called Nodes of Ranvier.
2. Corpus callosum is a sheet of Nervous tissue that unites the right and left Cerebral Hemisphere.
3. Cerebral aqueduct is found in Mid brain.
4. Dendrites transmit chemical impulse towards the cyton.
5. The lower end of medulla oblongata is filum terminate.

Answer:

1. False – The gaps on the axon are called Nodes of Ranvier.
2. True
3. False – Cerebral aqueduct is found in fore brain.
4. False – Dendrites transmit electrical impulse towards the cyton.
5. True

IV. Match the following:

Answer:
A. (ii)
B. (iv)
C. (i)
D. (v)
E. (iii)

V. Understand the assertion statement.Justify the reason given and choose the correct choice:

(a) Assertion is correct and reason is wrong.
(b) Reason is correct and the assertion is wrong.
(c) Both assertion and reason are correct.
(d) Both assertion and reason are wrong.
1. Assertion: Medulla oblongata is very important for our body.
Reason: Medulla oblongata regulates all in voluntary activities.
Answer:
(c) Both assertion and reason are correct.

2. Assertion: With drawl reflex is controlled by spinal cord.
Reason: Initially cerebrum is involved and require alertness for perform this reflex.
Answer:
(a) Assertion is correct and reason is wrong.

3. Assertion: In human being, cerebrum is most developed part of brain. Reason: Cerebrum is having large surface area and analyzing centre for maintaining body activity.
Answer:
(c) Both assertion and reason are correct.

VI Answer in one or two Sentences.

Question 1.
List the components of Nervous system.
Answer:
The components of Nervous system are brain, spinal cord and brain.

Question 2.
What is Motor or efferent neuron?
Answer:
Motor or efferent neuron carries impulses from the Central Nervous System to effector organs such as muscle fibre or gland.

Question 3.
What is synapse?
Answer:
The paint of contract between the neighbouring nerve cells is called synapse.

Question 4.
Name the outermost fibrous membrane of the brain.
Answer:
Dura mater.

Question 5.
Name the two components, ANS (Autonomic Nervous System).
Answer:
The two antagonistic components of ANS are sympathetic and para sympathetic system.

VII. Short answer questions:

Question 1.
What is Coordination?
Answer:
The various organs working in a systematic controlled and efficient way to produce proper response to various stimuli is called coordination.

Question 2.
What are simple or basic reflexes? Give a few actions, as examples.
Answer:
These simple reflexes are inbuilt and unlearned responses. Many of the actions we perform in our day to day life are simple reflexes, eg. Winking of eyes, Sneezing, Coughing and Yawning. We perform these actions without thinking.

Question 3.
Name the second largest part of the brain. What is its functions?
Answer:
The cerebellum is the second largest part of the brain, formed of two large-sized hemispheres and middle vermis. Maintenance of posture and balance, co-ordinate voluntary muscle activity, are some of the functions of the cerebellum.

Question 4.
Differentiate simple reflexes and conditioned reflexes.
Answer:

VIII. Higher Order Thinking Skills: (HOTS).

Question 1.
Give two examples of conditional reflexion.
Answer:

• Applying the brake while driving, when a red or yellow traffic light appears. We do not have to think about pressing the brake.
• Producing saliva is a response of a dog naturally have, when they smell or see food or when a bell sound was followed by food.

Question 2.
Injury to medulla oblongata can cause death. Why?
Answer:
Medulla Oblongata emerges from the base of the brain and joins the brain to the spinal cord. It controls the involuntary functions.

IX. Long Answer Question:

Question 1.
Classify peripheral nervous based on the nerves arising from the brain and the spinal cord.
Answer:
Peripheral nervous system is formed by the nerves arising from the brain and the spinal cord. The nerves arising from the brain are called cranial nerves. Nerves arising from spinal cord are called spinal nerves.

Cranial Nerves : In man, there are 12 pairs of cranial nerves. Some of the cranial nerves are sensory Eg: optic nerve which innervates the eye. Some are motor nerves which helps in rotation of eyeball. It also innervates the eye muscles, muscles of iris and tear gland.

Spinal Nerves : There are 31 pairs of spinal nerves. Each spinal nerve has a dorsal sensory root and the ventral motor root. The direction of impulses in dorsal spinal root is towards the spinal cord and in ventral spinal root away from the spinal cord.

Question 2.
List out the components of Nervous system and its function.
Answer:
The nervous system is formed of three distinct components namely the neurons, neuroglia and nerve fibres.
(i) Neuron or nerve cell : A neuron or nerve cell is the structural and functional unit of the nervous system. It is the longest cell of the human body with a length of over 100μm. These cells are highly specialised to detect, receive and transmit different kinds of stimuli. Information is conducted through neurons in the form of electrical impulses from one part of the body to another.

(ii) Neuroglia : Neuroglia are also called as glial cells. They are non¬exciting, supporting cell of the nervous system. They do not initiate or conduct nerve impulses.

(iii) Nerve fibres : The nerve fibres are the long slender processes of neurons. A number of nerve fibres are bundled up together to form nerves.

Question 3.
Explain Autonomic Nervous system.
Answer:
Autonomic Nervous System (ANS) is also called as visceral nervous system as it regulates the function of internal visceral organs of our body through its two antagonistic (opposite) components sympathetic and parasympathetic systems. They enable the body to perform rapid and specific visceral activities in order to maintain steady state. It controls the involuntary functions of the visceral organs.

Students can download 10th Science Chapter 14 Transportation in Plants and Circulation in Animals Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 14 Transportation in Plants and Circulation in Animals

Samacheer Kalvi 10th Science Transportation in Plants and Circulation in Animals Text Book Back Questions and Answers

I. Choose the best answer:

Question 1.
Active transport involves:
(a) movement of molecules from lower to higher concentration
(b) expenditure of energy
(c) it is an uphill task
(d) all of the above
Answer:
(d) all of the above

Question 2.
Water which is absorbed by roots is transported to aerial parts of the plant through ______.
(a) cortex
(b) epidermis
(c) phloem
(d) xylem.
Answer:
(d) xylem.

Question 3.
During transpiration there is loss of:
(a) carbon dioxide
(b) oxygen
(c) water
(d) none of the above
Answer:
(c) water

Question 4.
Root hairs are ______.
(a) cortical cell
(b) projection of the epidermal cell
(c) unicellular
(d) both b and c.
Answer:
(b) projection of the epidermal cell

Question 5.
Which of the following process requires energy?
(a) active transport
(b) diffusion
(c) osmosis
(d) all of them
Answer:
(a) active transport

Question 6.
The wall of the human heart is made of ______.
(a) Endocardium
(b) Epicardium
(c) Myocardium
(d) All of the above.
Answer:
(d) All of the above.

Question 7.
Which is the sequence of correct blood flow?
(a) ventricle – atrium – vein – arteries
(b) atrium – ventricle – veins – arteries
(c) atrium – ventricle – arteries – vein
(d) ventricles – vein – atrium – arteries
Answer:
(c) atrium – ventricle – arteries – vein

Question 8.
A patient with blood group O was injured in an accident and has blood loss. Which blood group the doctor should effectively use for transfusion in this condition?
(a) O group
(b) AB group
(c) A or B group
(d) all blood group.
Answer:
(d) all blood group.

Question 9.
‘Heart of heart’ is called:
(a) SA node
(b) AV node
(c) Purkinje fibres
(d) Bundle of His
Answer:
(a) SA node

Question 10.
Which one of the following regarding blood composition is correct?
(a) Plasma – Blood + Lymphocyte
(b) Serum – Blood + Fibrinogen
(c) Lymph – Plasma + RBC + WBC
(d) Blood – Plasma + RBC + WBC + Platelets.
Answer:
(d) Blood – Plasma + RBC+ WBG + Platelets.

II. Fill in the blanks:

1. ……….. involves evaporative loss of water from aerial parts.
2. Water enters the root cell through a ………. plasma membrane.
3. Structures in roots that help to absorb water are …………
4. Normal blood pressure is …………
5. The normal human heartbeat rate is about ……….. time per minute.

Answer:

1. Transpiration
2. Semipermeable
3. Root hairs
4. 120 mm / 80 mm Hg
5. 72 – 75 times

III. Match the following:

Section – I

Answer:
A. (ii)
B. (i)
C. (iv)
D. (iii)

Section – II

Answer:
A. (iv)
B. (i)
C. (ii)
D. (iii)
E. (viii)
F. (vii)
G. (v)
H. (vi)

IV. State whether True or False. If false write the correct statement:

1. The phloem is responsible for the translocation of food.
2. Plants lose water by the process of transpiration.
3. The form of sugar transported through the phloem is glucose.
4. In apoplastic movement the water travels through the cell membrane and enter the cell.
5. When the guard cells lose water the stoma opens.
6. Initiation and stimulation of heart beat take place by nerves.
7. All veins carry deoxygenated blood.
8. WBC defend the body from bacterial and viral infections.
9. The closure of the mitral and tricuspid valves at the start of the ventricular systole produces the first sound ‘LUBB’.

Answer:

1. True
2. True
3. False – The form of sugar transported through the phloem is sucrose.
4. False – Apoplastic movement does not involve crossing the cell membrane.
5. False – When the guard cells lose water the stoma closes.
6. False – Initiation and stimulation of heart beat take place by Sino-atrial node.
7. False – All veins carry deoxygenated blood except the pulmonary veins,
8. True
9. True.

V. Answer in a word or sentence:

Question 1.
Name two layered protective covering of human heart.
Answer:
Pericardium is the two layered protective covering of human heart.

Question 2.
What is the shape of RBC in human blood?
Answer:
The shape of RBC in human blood is biconcave and disc – shaped.

Question 3.
Why is the colour of the blood red?
Answer:
The blood is red in colour due to the presence of respiratory pigment – haemoglobin.

Question 4.
Which kind of cells are found in the lymph?
Answer:
Lymphocytes in the lymph, which defend the body from infection.

Question 5.
Name the heart valve associated with the major arteries leaving the ventricles.
Answer:
Aortic valve present at the base of aorta.

Question 6.
Mention the artery which supplies blood to the heart muscle.
Answer:
Coronary arteries.

VI. Short Answer Questions.

Question 1.
What causes the opening and closing of guard cells of stomata during transpiration?
Answer:
The general mechanism of stomatal movement is based on entry and exit of water molecules in guard cells. When the turgidity increases within the guard cells the stomata open. When the guard cells lose water it becomes flaccid and the stomata closes.

Question 2.
What is cohesion?
Answer:
The force of attraction between molecules of water is called Cohesion.

Question 3.
Trace the pathway followed by water molecules from the time it enters a plant root to the time it escapes into the atmosphere from a leaf.
Answer:
Soil → root hair → cortex → endodermis → Pericycle → xylem → stem → leaves.

Question 4.
What would happen to the leaves of a plant that transpires more water than its absorption in the roots?
Answer:
When transpiration exceeds than water absorption by roots, the plant dehydrates. It affects plant processes such as growth, Photosynthesis and transpiration.

Question 5.
Describe the structure and working of the human heart.
Answer:
The heart is thick muscular organ located in the thoracic cavity. It is covered by a two layered sac called pericardium. The heart is four chambered with two auricles and two ventricles. Right Auricle receives deoxygenated blood from superior and inferior vena cava and passes to right ventricles from right ventricles impure blood passes to pulmonary artery and reaches the lungs.

Question 6.
Why is the circulation in man referred to as double circulation?
Answer:
The blood circulates twice, through the heart in one complete cycle, in the circulation of blood in man. So it is called double circulation.

Question 7.
What are heart sounds? How are they produced?
Answer:
‘Lubb’ and ‘Dupp’ are the sounds of the heart. ‘Lubb’ sound is produced by the ventricle- contraction. It arises due to closing of mitral and tricuspid valve.
‘Dupp’ is produced by ventricular diastole. This arises due to the closing of the semi-lunar valves of two auricles.

Question 8.
What is the importance of valves in the heart?
Answer:
The valves are the muscular flaps, that regulate the flow of blood in a single direction and prevent backflow of blood.

Question 9.
Who discovered Rh factor? Why was it named so?
Answer:
Landsteiner and Wiener discovered Rh factor of blood in 1940. Rh factor is a protein CD antigen present on the surface of the red blood cells in majority of humans. This protein is similar to the protein present in Rhesus monkey, hence the term Rh.

Question 10.
How are arteries and veins structurally different from one another?
Answer:

Question 11.
Why is the Sinoatrial node called the pacemaker of the heart?
Answer:
Sinoatrial node is called the pacemaker of the heart because it is capable of initiating impulse, which can stimulate the heart muscles to contract.

Question 12.
Differentiate between systemic circulation and pulmonary circulation.
Answer:

Question 13.
The complete events of the cardiac cycle last for 0.8 sec. What is the timing for each event?
Answer:

1. Atrial Systole: Contraction of auricles (0.1 sec)
2. Ventricular Systole: Contraction of ventricles (0.3 sec)
3. Ventricular diastole: Relaxation of Ventricles (0.4 sec).

VII. Give reasons for the following statements:

Question 1.
Minerals cannot be passively absorbed by the roots.
Answer:
All minerals cannot be passively absorbed by the roots because, minerals are present in the soil as charged particles that cannot move across the cell membranes and the concentration of minerals in the soil is usually lower than the. concentration of minerals in the root. So, the minerals enter the root by active absorption through the cytoplasm of epidermal cells which needs energy.

Question 2.
Guard cells are responsible for opening and closing of stomata.
Answer:
Guard cells are responsible for the opening and closing of stomata because, during transpiration, the movement of ions (Potassium) in and out of the guard cells causes the opening and closing of Stomata. When the water moves inside the guard cells, causing them to swell up and become turgid making the stomata open. When guard cells cause water to move out of the cell and make guard cells shrunk and stomata pores close.

Question 3.
The movement of substances in the phloem can be in any direction.
Answer:
Phloem transports food from the source to sink. The source is part in which plant synthesize food, sink is the part that needs or stores food. Since the source-sink relationship is variable, the direction of movement in the Phloem can be upwards or downwards, i.e., bidirectional.

Question 4.
Minerals in the plants are not lost when the leaf falls.
Answer:
Minerals like Phosphorus, Sulphur, Nitrogen and Potassium are remobilised in the soil from older dying leaves to younger leaves. This phenomenon is seen in deciduous plants. So minerals in the plants are not lost, when the leaf falls.

Question 5.
The walls of the right ventricle are thicker than the right auricles.
Answer:
Because the right ventricle have to pump out the deoxygenated blood with force away from the heart through pulmonary artery to lungs.

Question 6.
Mature RBC in mammals does not have cell organelles.
Answer:
Mature RBC in mammals does not have cell organelles because

• The lack of Nucleus in RBC makes the cells, biconcave and disc – shaped. RBC involved in the transport of oxygen from lungs to tissues.
• They do not have cell organelles in order to accommodate maximum space for haemoglobin.
• The loss of endoplasmic reticulum allows more flexibility, for RBC to move through narrow capillaries.

VIII. Long Answer Questions:

Question 1.
How do plants absorb water? Explain.
Answer:
Water present in the soil must reach the xylem of roots. Root hair is in contact with soil water. Their cell wall is thin and water easily diffuses in the passage of water from the soil to leaf is
Soil water → Root hair → Epidermis → Cortex → Endodermis → Pericycle → Xylem → Stem and leaf.
Once water is absorbed by the root hairs, it can move deepers into root layers by two pathways. Apoplast and Symplast.

1. Apoplast : This is the non living path in plants. It occurs through the intercellular spaces and walls of the cells. This movement dependent on the gradient.
2. Symplast : This is the living passage. The movement of water from cell to cell through plasmodesmato and cytoplasm, Movement is again down a potential gradient.

Question 2.
What is transpiration? Give the importance of transpiration.
Answer:
Transpiration is the evaporation of water in plants through stomata in the leaves.
Importance of Transpiration

• Creates transpirational pull for the transport of water.
• Supplies water for photosynthesis.
• Transports minerals from the soil to all parts of the plant.
• Cools the surface of the leaves by evaporation.
• Keeps the cells turgid; hence, maintains their shape.

Question 3.
Why are leucocytes classified as granulocytes and agranulocytes? Name each cell and mention its functions.
Answer:
Depending on the presence and absence of granules, leucoytes are divided into two types Granulocytes and Agranulocytes.
Granulocytes : They are characterised by the presence of granules in cytoplasm. The granulocytes include neutrophils, eosinophils and basophils.

1. Neutrophils : They constitute about 60-65% of total WBC’s. They are large and have many lobed nucleus. They are phagocytic in nature and appear in large,number in and around the infected tissue.
2. Eosinophils : They have bilobed nucleus and constitute about 2-3% of total WBC’s. Eosinophil increase during certain types of parasitic infection and allergic reaction. It bring about detoxification of toxin.
3. Basophils: Basophil have lobed nucleus. They form 0.5 – 1.0% of the total leucocytes. They release chemicals during the process of inflammation.

Agranulocytes : They are characterised by the absence of granules in the cytoplasm. These are of two types Lymphocytes and Monocytes.

1. Lymphocytes: These are about 20-25% of the total leucocytes. They produce antibodies during bacterial and viral infections.
2. Monocytes: They are the largest leucocytes and amoeboid in shape. These cells form 5-6% of the total leucocytes. They are phagocytic and can engulf bacteria.

Question 4.
Differentiate between systole and diastole. Explain the conduction of the heartbeat.
Answer:
One complete contraction (Systole) and relaxation (diastole) of the atrium and ventricles of the heart constitutes Heartbeat. The human heart is myogenic. Contraction is initiated by the sino – atrial (SA) node, which is situated in the wall of the right atrium, near the opening of the superior vena cava. SA node is broader at the top and tapering below and made up of thin fibres.

SA node acts as the ‘pacemaker’ of the heart because it is capable of initiating impulse which can stimulate the heart muscles to contract. The impulse spreads like a wave of contraction over the right and left atrial wall, pushing the blood, through the atrioventricular valves into the ventricles and the same wave from SA node reaches the atrioventricular node (AV), to emit an impulse of contraction, spreading to the ventricular muscle, through the atrioventricular bundle and the Purkinje fibres. The expansion of the artery every time, the blood is forced into the arteries, is called pulse. Normal pulse rate ranges from 70 – 90 / min.

Question 5.
Enumerate the functions of blood.
Answer:

1. Transport of respiratory gases (Oxygen and CO₂).
2. Transport of digested food materials to the different body cells.
3. Transport of hormones.
4. Transport of nitrogenous excretory products like ammonia, urea and uric acid.
5. It is involved in protection of the body and defense against diseases.
6. It acts as buffer and also helps in regulation of pH and body temperature.
7. It maintains proper water balance in the body.

IX. Assertion and Reasoning:

Direction: In each of the following questions a statement of assertion (A) is given and a corresponding statement of reason (R) is given just below it. Mark the correct statement as.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
1. Assertion: RBC plays an important role in the transport of respiratory gases.
Reason: RBC do not have cell organelles and nucleus.
Answer:
(a) If both A and R are true and R is correct explanation of A.

2. Assertion: Persons with AB blood group are called an universal recipients, because they can receive blood from all groups.
Reason: Antibodies are absent in persons with AB blood group.
Answer:
(a) If both A and R are true and R is correct explanation of A.

X. Higher Order Thinking Skills (HOTS):

Question 1.
When any dry plant material is kept in water, they swell up. Name and define the phenomenon involved in this change.
Answer:
The process is imbibition’. The type of diffusion in which a solid absorbs water and gets swelled up is Imbibition.

Question 2.
Why are the walls of the left ventricle thicker than the other chambers of the heart?
Answer:
The walls of the left ventricle are about three times thicker than the right ventricle. The left ventricle gives rise to the aorta, which carries oxygenated blood, to various organs of the body. The ventricle walls are thick because they have to pump out blood with force away from the heart.

Question 3.
Doctors use stethoscope to hear the sound of the heart. Why?
Answer:
A stethoscope is an instrument used to detect the sound produced by the internal organs of human body. It is an useful diagnostic tool to identify and localize health problems and diagnose disease.

Question 4.
How do the pulmonary artery and pulmonary vein differ in their function when compared to a normal artery and vein?
Answer:

• All arteries carry oxygenated blood, except pulmonary arteries, which carry deoxygenated blood from the right ventricle to the lungs.
• All veins carry deoxygenated blood, except pulmonary veins, which carry oxygenated blood from the lungs and to the left atrium of the Heart.

Question 5.
Transpiration is a necessary evil in plants. Explain.
Answer:
The water is lost from the leaves due to transpiration, pressure is created in, at the top to pull more water from the xylem to the leaves through the process of transpiration pull. This ensure the continuous flow of water from the roots of the leaves.

Samacheer Kalvi 10th Science Transportation in Plants and Circulation in Animals Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
Seed swells when placed in water due to:
(a) osmosis
(b) imbibition
(c) hydrolysis
(d) all of these
Answer:
(b) imbibition

Question 2.
Root hairs occurs in:
(a) Meristematic zone
(b) Cell elongation zone
(c) Cell maturation zone
(d) Old root
Answer:
(c) Cell maturation zone

The other name for Red blood corpuscles (RBC) is called ______.
Answer:
Erythrocytes.

Question 3.
Water in plants is transported by ascent of sap takes place through:
(a) cambium
(b) xylem
(c) phloem
(d) epidermis
Answer:
(b) xylem

Question 4.
Absorption of water is increased when:
(a) transpiration is increased
(b) photosynthesis is increased
(c) respiration is increased
(d) root pressure is increased
Answer:
(a) transpiration is increased

Question 5.
Opening of stomata is due to:
(a) Turgidity of guard cells
(b) Size of guard cells
(c) Number of guard cells
(d) Amount of CO₂ in the atmosphere.
Answer:
(a) Turgidity of guard cells

Question 6.
Guard cells help in:
(a) Fighting against infection
(b) Guttation
(c) Protecting against grazing
(d) Transpiration
Answer:
(d) Transpiration

Question 7.
Photosynthetic food material is transported in the form of:
(a) Glucose
(b) Sucrose
(c) Starch
(d) Fructose
Answer:
(b) Sucrose

Question 8.
Coronary artery supplies blood to:
(a) Mammary glands
(b) Rib muscles
(c) Skin
(d) Heart
Answer:
(d) Heart

Question 9.
All arteries carry oxygenated blood except:
(a) systematic
(b) hepatic
(c) pulmonary
(d) cardiac
Answer:
(c) pulmonary

Question 10.
The colour of lymph is:
(a) white
(b) pale yellow
(c) colourless
(d) milky
Answer:
(c) colourless

Question 11.
An artery can be distinguished from a vein in having:
(a) thicker wall
(b) elastic vessels
(c) no valves
(d) all of the above
Answer:
(d) all of the above

Question 12.
Purkinje fibres mainly help in contraction of:
(a) right auricle
(b) left auricle
(c) ventricles
(d) Aorta
Answer:
(c) ventricles

Question 13.
The ‘Lubb’ and ‘Dupp’ heart sound are due to:
(a) opening of heart valves
(b) action of papillary’ muscles
(c) closing of heart valves
(d) activity of pace maker
Answer:
(c) closing of heart valves

Question 14.
The closed circulatory system occurs in:
(a) cockroach
(b) fish
(c) mosquito
(d) house fly
Answer:
(b) fish

Question 15.
Normal pulse rate is:
(a) 80 mm Hg
(b) 120 mm Hg
(c) 40 mg Hg
(d) 90 mm Hg
Answer:
(d) 90 mm Hg

Question 16.
In the ABO system of blood groups, of both antigens are present but no antibody, the blood group of the individual would be?
(a) B
(b) O
(c) AB
(d) A
Answer:
(c) AB

Question 17.
Arteries are branches of:
(a) capillaries
(b) veins
(c) aorta
(d) none of these
Answer:
(c) aorta

Question 18.
Which type of WBCs are found in maximum number?
(a) Monocytes
(b) Basophils
(c) Eosinophils
(d) Neutrophils
Answer:
(d) Neutrophils

Question 19.
Which of the following are granular WBCs?
(a) Neutrophils, Basophils, Lymphocytes
(b) Eosinophil, Basophil, Monocytes
(c) Basophils, Monocytes, Lymphocytes
(d) Neutrophils, Eosinophil, Basophil
Answer:
(d) Neutrophils, Eosinophil, Basophil

Question 20.
RBCs are concerned with carriage of gases.
(a) CO₂
(b) O₂
(c) Respiratory
(d) CO₂ and SO₂
Answer:
(c) Respiratory

II. Fill in the blanks:

1. The contraction of heart is called ………..
2. Oxygenated blood is carried by ………..
3. Sphygmomanometer measures ………..
4. Heart of man is ………..
5. Pace maker of heart is ………..
6. The life span of RBC in human is ……… days.
7. Pulmonary artery carry ………….. blood.
8. ………. discovered the circulation of blood in man.
9. Semilunar valve is present at the base of ………….
10. Human heart beats ………. times in a minute at rest.
11. Red blood pigment is ………..
12. Transpiration helps in the absorption and ………… movement of water and minerals.
13. Water in plants is transported by ascent of sap takes place through ……….
14. The absorption water due to expenditure of energy is called ………….
15. In plants, the translocation of organic solutes takes place through ………….
Answer:
1. systole
2. pulmonary vein
3. blood pressure
4. myogenic
5. sino atrial node
6. 120
7. deoxygenated
8. William Harvey
9. Pulmonary artery
10. 72
11. Haemoglobin
12. upward
13. xylem
14. active absorption
15. phloem

III. Match the following:

Question 1.
Match the Column I with Column II.

Answer:
A. (iv)
B. (iii)
C. (i)
D. (ii)

Question 2.
Match the Column I with Column II.

Answer:
A. (iv)
B. (iii)
C. (i)
D. (v)
E. (ii)

IV. State whether true or false. If false write the correct statement:

1. The human heart beats 72 times per minute.
2. Right half of heart receives and pu mps off oxygenated blood.
3. Between right auricle and right ventricle seen Mitral valve.
4. The force of attraction between water molecule is cohesion.
5. By passive transport sucrose moves into the cells where it is utilised or stored.

Answer:

1. True
2. False – Right half of heart receives and pumps off deoxygenated blood.
3. False – Between right auricle and right ventricle seen tricuspid valve.
4. True
5. False – By active transport sucrose moves into the cells where it is utilised or stored.

V. Creative Question:

Question 1.
Origin of heart beat and its conduction is represented by:
(a) AV node → Bundle of His → SA node → Purkinje fibres
(b) SA node → Purkinje fibres → AV node → Bundle of His
(c) Purkinje fibres → Purkinje node → AV fibres → Bundle of His
(d) SA node → AV node → Bundle of His → Purkinje fibres
Answer:
(d) SA node → AV node → Bundle of His → Purkinje fibres

Question 2.
The cardiac pacemaker in a patient fails to function normally. The doctors find that an artificial pacemaker is to be grafted in him. It is likely that it will be drafted at the site of:
(a) Purkinje system
(b) Sinu atrial node
(c) Atrio ventricular node
(d) Atrio ventricular bundle
Answer:
(b) Sinu atrial node

Question 3.
Doctor use stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when:
(a) AV node receives signal from SA node
(b) AV valves open up
(c) Ventricular walls vibrate due to rushing in of blood from atria
(d) Semi lunar valves close down after the blood flows into vessels from ventricles
Answer:
(d) Semi lunar valves close down after the blood flows into vessels from ventricles

VI. Assertion and Reason:

(a) If both the assertion and the reason are true and the reason is the correct explanation of assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.
1. Assertion: RBC impart red colour to the blood due to the presence of respiratory pigment haemoglobin.
Reason: The young RBC contain nucleus in man.
Answer:
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.

2. Assertion: Osmosis is the movement of solvent molecule from higher concentration to lower concentration.
Reason: Osmosis is the active movement of water.
Answer:
(c) Assertion is true, but the reason is false.

VII. Answer in a Sentence:

Question 1.
Name the components of circulatory system.
Answer:
The circulation system consists of the circulating fluids, the blood and lymph, the heart and the blood vessels namely arteries, veins and capillaries.

Question 2.
What is the Ascent of Sap?
Answer:
The upward movement of water and minerals from roots to different plant parts is called ascent of sap.

Question 3.
Mention the composition of plasma.
Answer:
Organic substances like protein, glucose, urea, enzyme, hormones, vitamins and minerals are present in plasma.

Question 4.
Define Adhesion?
Answer:
The force of attraction between molecules of different substances is called adhesion.

Question 5.
Why are auricles and ventricles separated by auricular and ventricular septum?
Answer:
The separation of chamber avoids mixing of oxygenated and deoxygenated blood.

Question 6.
What is Single Circulation?
Answer:
In fishes, amphibians and certain reptiles, the oxygenated and deoxygenated blood are mixed ‘ and pass through the heart only once, is called Single Circulation.

Question 7.
Name the instruments used to measure blood pressure.
Answer:
Sphygmomanometer is a clinical instruments used to measure blood pressure when a person is in a relaxed and resting condition. Normal blood pressure in human is 120 mm/ 80 mm Hg.

Question 8.
Which blood group is called as ‘Universal Donor’ and ‘Universal Recipient’.
Answer:
Person with ‘O’ blood group are called Universal Donor.
Person with ‘AB’ blood group are called Universal Recipient.

Question 9.
What is Pulse?
Answer:
During the expansion of the artery, every time, the blood is forced into the arteries is called pulse.

Question 10.
What is transpiration puil?
Answer:
Transpiration through stomata creates vacuum which creates a suction called transpiration pull.

Question 11.
What are Rh antibodies?
Answer:
Rh-negative persons do not have Rh antigen on the surface of RBC. Antibodies developed against this Rh antigen is called Rh antibodies.

Question 12.
What is Adhesion?
Answer:
The force of attraction between molecules of different substances is called . adhesion.

VIII. Short answer question:

Question 1.
What is blood pressure?
Answer:
Blood pressure is the force exerted during the flow of blood against the lateral walls of arteries. The blood pressure is high in the arteries gradually drop in the arterioles and capillaries and become very low in the veins. Blood pressure varies during conditions of physical exercise, anxiety, emotions, stress and sleep. Increase in blood pressure is known as hypertension and decrease in blood pressure is termed as hypotension.

Question 2.
Distinguish between open and closed circulation.
Answer:

Question 3.
Explain the phenomenon of Guttation.
Answer:
The Guttation is a phenomenon caused due to root pressure. It takes place through a specialized cells called hydathodes. Dews on the leaves of grass seen in the early morning, when the climate is humid and excess of water in the soil is an example of Guttation.

Question 4.
What is Coronary circulation?
Answer:
The supply of blood to the heart muscles is called as coronary circulation. Cardiac muscles receives oxygenated blood from coronary arteries that originate from the aortic arch. Deoxygenated blood from the cardiac muscles drains into the right atrium by the coronary sinuses.

IX. Long answer questions:

Question 1.
What is lymph? Write its functions.
Answer:
Lymph is a colourless fluid formed when plasma, proteins and blood cells escape into intercellular spaces in the tissues through the pores present in the walls of capillaries.
Functions of Lymph:

1. Supplies nutrition and oxygen to those parts where blood cannot reach.
2. It drains away excess tissue fluid and metabolites and returns proteins to the blood from tissue spaces.
3. The lymph also carries absorbed fats from small intestine to the blood. The lymphatic capillaries of intestinal villi (lacteals) absorb digested fats.
4. Lymphocytes in the lymph defend the body from infections.

Question 2.
(a) Name the main two components of blood.
(b) What does plasma contain?
Answer:
(a) 1. The fluid plasma
2. Formed elements (blood cells)

• RBC
• WBC
• Blood platelets

(b) Plasma is slightly alkaline, containing non – cellular substance, constitute 55 % of the blood. Organic substances like Proteins, Glucose, Urea, Enzymes, Hormones, Vitamins and Minerals are present in the Plasma.

Question 3.
Demonstrate the process of osmosis with thistle funnel.
Answer:
Aim : To demonstrate the process of osmosis, using Thistle funnel.
Materials Required : Beaker, Thistle funnel, semi permeable membrane, sucrose solution.
Procedure : A thistle funnel whose mouth is covered with a semipermeable membrane, is filled with sucrose solution. It is kept inverted in a beaker containing water.
Observation : The water will diffuse across the membrane due to osmosis and raise the level of the solution in the funnel.
Inference : Raise of liquid in the funnel indicates the process of osmosis.

Question 4.
Explain Double circulation.
Answer:
Diagrammatic representation of the double circulation.

Question 5.
Explain the steps involved in Ascent of sap.
Answer:
The upward movement of water, and minerals from roots to different plant parts is called ascent of sap. A number of factors play a role in ascent of sap and it takes places in following steps.
Root Pressure : Water from soil enters the root hairs due to osmosis. Root pressure is responsible for movement of water up to the base of the stem.

Capillary Action : Water or any liquid rises in a capillary tube because of physical forces, this phenomenon is called capillary action. In the same way, in stem water rises up to certain height because of capillary’ action.
Adhesion-cohesion of Water Molecules : Water molecules form a continuous column in the xylem because of forces of adhesion and cohesion among the molecules.
Cohesion : The force of attraction between molecules of water is called cohesion.
Adhesion : The force of attraction between molecules of different substances is called adhesion.Water molecules stick to a xylem because of force of adhesion.

Question 6.
Explain the causes of the sound of the Heart.
Answer:
The rhythmic closure and opening of the valves cause the sound of the heart.

• The first sound ‘LUBB’ is produced by the closure of the tricuspid and bicuspid valves, after the beginning of ventricular systole. It is a longer duration.
• The second sound ‘DUPP’ is produced by the closure of semilunar valves, at the end of ventricular systole. It is of short duration.

X. Higher Order Thinking Skills (HOTS)

Question 1.
An unconscious patient is rushed into the emergency room and need a fast blood transfusion. Because there is no time to check her medical history or determine her blood type, which type of blood should you as her doctor, give?
Answer:
O^+ve, it is universal donor. In O group individuals, Antigen A or B are absent on the surface of RBC. However the plasma contains both antibodies a and b.

Question 2.
What are the factors affecting the Ascent of Sap?
Answer:

• High Temperature
• Atmospheric Pressure
• Wind Velocity
• Low atmospheric humidity
• Soil water deficit.

Question 3.
Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements.
Answer:
Both processes can happen together because the diffusion co-efficient of water and CO₂ is different.

Question 4.
Write a few Strategies, to prevent heart disease.
Answer:

• Exercise for about 30 minutes every day.
• Smoking or use of Tobacco should be avoided.
• Eat a heart-healthy diet – Avoid too much of salt or sugar, use of a diet rich in Vegetables and Fruits.
• Maintain a healthy weight.
• Get enough quality sleep.
• Manage Stress.
• Get regular health screenings (B.P. monitoring, Cholesterol level, Diabetes Screening etc.).

XI. Give reason:

Question 1.
Valves are important in human heart. Give reason.
Answer:
The valves will prevent the back flow of blood.

Question 2.
During rainy season wooden door generally swells up – Give reason.
Answer:
It is due to imbibition. It is a type of diffusion in which a solid absorbs water and gets swelled up.

Question 3.
Para sympathetic neural signals affects the working of the heart. Give reason.
Answer:
It reduce both heart rate and cardiac output.

Question 4.
Grapes placed in salt solution shrink. Give reason.
Answer:
It is due to exosmosis.

Question 5.
Why WBC’s are known as phagocytes?
Answer:
WBC produce antibodies during bacterial and viral infection and engulf the germs.

Students can Download Samacheer Kalvi 10th Maths Model Question Paper 5 English Medium Pdf, Samacheer Kalvi 10th Maths Model Question Papers helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamil Nadu Samacheer Kalvi 10th Maths Model Question Paper 5 English Medium

Instructions

• The question paper comprises of four parts.
• You are to attempt all the parts. An internal choice of questions is provided wherever applicable.
• All questions of Part I, II, III and IV are to be attempted separately.
• Question numbers 1 to 14 in Part I are Multiple Choice Quèstions of one-mark each. These are to be answered by choosing the most suitable answer from the given four alternatives and.writing the option code and the corresponding answer.
• Question numbers 15 to 28 in Part II àre two-marks questions. These are to be answered in about one or two sentences.
• Question numbers 29 to 42 in Part III are five-marks questions. These are to be answered in about three to five short sentences.
• Question numbers 43 to 44 in Part IV are eight-marks questions. These are to be answered in detail. Draw diagrams wherever necessary.

Time: 3 Hours
Maximum Marks: 100

PART – I

I. Choose the correct answer. Answer all the questions. [14 × 1 =14]

Question 1.
The range of the relation R = {(x, x²) x is a prime number less than 13} is ………… .
(1) {2, 3, 5, 7}
(2) (2, 3, 5, 7, 11}
(3) {4,9,25,49, 121}
(4) {1, 4, 9, 25, 49, 121}
Answer:
(3) {4,9,25,49, 121}

Question 2.
If g = {(1,1),(2, 3),(3,5),(4,7)} is a function given by g(x) = αx + β then the values of α and β are ……….. .
(1) (-1,2)
(2) (2,-1)
(3) (-1,-2)
(4) (1,2)
Answer:
(2) (2,-1)

Question 3.
The sum of the exponents of the prime factors in the prime factorization of 1729 is ……….. .
(1) 1
(2) 2
(3) 3
(4) 4
Answer:
(3) 3

Question 4.
The next term of the sequence \(\frac{3}{16}, \frac{1}{8}, \frac{1}{12}, \frac{1}{18}\) is ……….. .
(1) \(\frac{1}{24}\)
(2) \(\frac{1}{27}\)
(3) \(\frac{2}{3}\)
(4) \(\frac{1}{81}\)
Answer:
(2) \(\frac{1}{27}\)

Question 5.
If (x – 6) is the HCF of x² – 2x – 24 and x² – kx – 6 then the value of k is ……….. .
(1) 3
(2) 5
(3) 6
(4) 8
Answer:
(2) 5

Question 6.
The solution of (2x – 1)² = 9 is equal to ……….. .
(1) -1
(2) 2
(3) -1,2
(4) None of these
Answer:
(3) -1,2

Question 7.
In a given figure ST || QR, PS = 2 cm and SQ = 3 cm. Then the ratio of the area of ∆PQR to the area of ∆PST is ……….. .

(1) 25 : 4
(2) 25 : 7
(3) 25 :11
(4) 25 : 13
Answer:
(1) 25 : 4

Question 8.
The slope of the line joining (12, 3), (4, a) is \(\frac { 1 }{ 8 }\). The value of ‘a’ is ……….. .
(1) 1
(2) 4
(3) -5
(4) 2
Answer:
(4) 2

Question 9.
If sin θ + cos θ = a and sec θ + cosec θ = b, then the value of b (a² – 1) is equal to ……….. .
(1) 2 a
(2) 3 a
(3) 0
(4) 2 ab
Answer:
(1) 2 a

Question 10.
The curved surface area of a right circular cone of height 15 cm and base diameter 16 cm is ……….. .
(1) 60π cm²
(2) 68π cm²
(3) 120π cm²
(4) 136π cm²
Answer:
(4) 136π cm²

Question 11.
The sum of all deviations of the data from its mean is ……….. .
(1) always positive
(2) always negative
(3) zero
(4) non-zero integer
Answer:
(3) zero

Question 12.
If \(\left( \begin{matrix} x+y & x-y \\ 7 & 6 \end{matrix} \right) =\left( \begin{matrix} 10 & 2 \\ 7 & z \end{matrix} \right) \) then x, y, z are ……….. .
(1) 4, 6, 6
(2) 6, 6, 4
(3) 6, 4, 6
(4) 4, 4, 6
Answer:
(3) 6, 4, 6

Question 13.
If the n^th term of a sequence is 100n + 10 then the sequence is ……….. .
(1) an A.P.
(2) a G.P.
(3) a constant sequence
(4) neither A.P. nor G.P.
Answer:
(1) an A.P.

Question 14.
Probability of getting 3 heads or 3 tails in tossing a coin 3 times is ……….. .
(1) \(\frac { 1 }{ 8 }\)
(2) \(\frac { 1 }{ 4 }\)
(3) \(\frac { 3 }{ 8 }\)
(4) \(\frac { 1 }{ 2 }\)
Answer:
(2) \(\frac { 1 }{ 4 }\)

PART – II

II. Answer any ten questions. Question No. 28 is compulsory. [10 × 2 = 20]

Question 15.
Let A = {x ∈ W / x < 2}, B = {x ∈ N / 1 < x ≤ 4} and C = {3, 5} find the value of (A × C) ∪ (B × C)
Answer:
A × C = {0,1} × {3,5}
= {(0,3 (0,5) (1,3) (1,5)}
B × C= (2,3,4) × (3,5)
= {(2,3) (2,5) (3,3) (3,5) (4,3) (4,5)}
(A × C) ∪ (B × C) = {(0,3) (0,5) (1,3) (1,5) (2,3) (2,5) (3,3) (3,5) (4,3) (4,5)}

Question 16.
Find k if fof(k) = 5 where f(k) = 2k – 1.
Answer:
fof(k) = f(f(k)) = 2(2k – 1)-1 = 4k – 3.
Thus, fof(k) = 4k – 3
But, it is given that fof(k) = 5
∴ 4k – 3 = 5 ⇒ k = 2.

Question 17.
Find the sum of the following 6 + 13 + 20 +…. + 97
Answer:
Here a = 6, d = 13 – 6 = 7, l = 97
n = \(\frac{l-a}{d}+1\)
= \(\frac{97-6}{7}+1\) = \(\frac{91}{7}+1\) = 13 + 1 = 14
S_n = \(\frac{n}{2}\)(a + l)
S_n = \(\frac{14}{2}\)(6 + 97) = 7 × 103 = 721

Question 18.
Rekha has 15 square colour papers of sizes 10 cm, 11 cm, 12 cm, …,.24 cm. How much area can be decorated with these colour papers?
Answer:
Area of 15 square colour papers
= 10² + 11² + 12² + …. + 24²
= (1² + 2² + 3² + …. + 24²) – (1² + 2² + 9²)
= \(\frac{24 \times 25 \times 49}{6}-\frac{9 \times 10 \times 19}{6}\)
=4 × 25 × 49 – 3 × 5 × 19
= 4900 – 285
= 4615
Area can be decorated is 4615 cm²

Question 19.
Simplify \(\frac{x+2}{4 y} \div \frac{x^{2}-x-6}{12 y^{2}}\)
Answer:

x² – x – 6 = (x – 3) (x + 2)
= \(\frac{x+2}{4 y} \div \frac{x^{2}-x-6}{12 y^{2}}=\frac{x+2}{4 y}+\frac{(x-3)(x+2)}{12 y^{2}}\)
= \(\frac{(x+2)}{4 y} \times \frac{12 y^{2}}{(x-3)(x+2)}\)
= \(\frac{3 y}{x-3}\)

Question 20.
Solve \(\frac{x}{x-1}+\frac{x-1}{x}=2 \frac{1}{2}\)
Answer:
Let y = \(\frac{x}{x-1}\) then \(\frac{1}{y}=\frac{x-1}{x}\)
Therefore, \(\frac{x}{x-1}+\frac{x-1}{x}=2 \frac{1}{2}\) becomes \(y+\frac{1}{y}=\frac{5}{2}\)
2y² – 5y + 2 = 0 then, y = \(\frac{1}{2}, 2\)
\(\frac{x}{x-1}=\frac{1}{2}\) we get, 2x = x – 1 implies x = – 1
\(\frac{x}{x-1}=2\) we get, x = 2x – 2 implies x = 2
∴ The roots are x = -1, 2

Question 21.
Construct a 3 × 3 matrix whose elements are given by a_ij = |i – 2j|
Answer:
a_ij = |i – 2j|
The general 3 × 3 matrices is
A = \(\left( \begin{matrix} { a }_{ 11 } & { a }_{ 12 } & { a }_{ 13 } \\ { a }_{ 21 } & { a }_{ 22 } & { a }_{ 23 } \\ { a }_{ 31 } & { a }_{ 32 } & { a }_{ 33 } \end{matrix} \right)\)
a₁₁ = |1 – 2(1)| = |1 – 2| = |-1| = 1
a₁₂ = |1 – 2(2)| = |1 – 4| = |-3| = 3
a₁₃ = |1 – 2(3)| = |1 – 6| = |-5| = 5
a₂₁ = |2 – 2(1)| = |2 – 2| = 0
a₂₂ = |2 – 2(2)| = |2 – 4| = |-2| = 2
a₂₃ = |2 – 2(3)| = |2 – 6| = |-4| = 4
a₃₁ = |3 – 2(1)| = |3 – 2| = |1| = 1
a₃₂ = |3 – 2(2)| = |3 – 4| = |-1| = 1
a₃₃ = |3 – 2(3)| = |3 – 6| = |-3| = 3
The required matrix A = \(\left[ \begin{matrix} 1 & 3 & 5 \\ 0 & 2 & 4 \\ 1 & 1 & 3 \end{matrix} \right] \)

Question 22.
The length of the tangent to a circle from a point P, which is 25 cm away from the centre is 24 cm. What is the radius of the circle?
Answer:

Let the radius AB be r. In the right ∆ ABO,
OB² = OA² + AB²
25² = 24² + r²
25² – 24² = r²
(25 + 4) (25 – 24) = r²
r = √49 = 7
Radius of the circle = 7 cm

Question 23.
If the straight lines 12y = – (p + 3)x + 12, 12x – 7y = 16 are perpendicular then find ‘p’.
Answer:
Slope of the first line 12y = -(p + 3)x + 12
y = \(-\frac{(p+3) x}{12}+1\) (comparing with y = mx + c)
Slope of the second line (m₁) = \(\frac{-(p+3)}{12}\)
Slope of the second line 12x – 7y = 16
(m₂) = \(\frac{-a}{b}=\frac{-12}{-7}=\frac{12}{7}\)
Since the two lines are perpemdicular.
m₁ × m₂ = -1
\(\frac{-(p+3)}{12} \times \frac{12}{7}=-1 \Rightarrow \frac{-(p+3)}{7}=-1\)
-(p + 3) = -7
– p – 3 = – 7 ⇒ -p = -7 + 3
– p = -4 ⇒ p = 4
The value of p = 4

Question 24.
Prove that 1 + \(\frac{\cot ^{2} \theta}{1+\csc \theta}\) = cosec θ
Answer:

Question 25.
Find the standard deviation of first 21 natural numbers.
Answer:
Here n = 21
Standard deviation of the first ‘n’ natural numbers,
= \(\sqrt{\frac{n^{2}-1}{12}}\)
1,2,3,4, ……. , 21 = \(\sqrt{\frac{21^{2}-1}{12}}=\sqrt{\frac{441-1}{12}}=\sqrt{\frac{440}{12}}\)
= \(\sqrt{36.666}\) = \(\sqrt{36.67}\)
= 6.055 = 6.06
Standard deviation of first 21 natural numbers = 6.06

Question 26.
How many litres of water will a hemispherical tank hold whose diameter is 4.2m?
Answer:
Radius of the tank = \(\frac{4.2}{2}\) = 2.1 m
Volume of the hemisphere = \(\frac{2}{3}\) πr³ cu. unit
= \(\frac{2}{3} \times \frac{22}{7}\) × 2.1 × 2.1 × 2.1 m³
= 19.404 m³
= 19.4o4 × 1000 litre
= 19,4o4 litres

Question 27.
A two digit number is formed with the digits 2, 5, 9 (repetition is allowed). Find the probability that the number is divisible by 2.
Answer:
Sample space (S) = {22, 25, 29, 55, 59, 52, 99, 92, 95}
n(S) = 9
Let A be the event of getting number divisible by 2
A = {22,52,92}
n(A) = 3
P(A) = \(\frac{n(\mathrm{A})}{n(\mathrm{S})}=\frac{3}{9}=\frac{1}{3}\)

Question 28.
Solve √x + 5 = 2x + 3 using formula method.
Answer:
\(\sqrt{x+5}\) = 2x + 3
\((\sqrt{x+5})^{2}\) = (2x + 3)²
x + 5 = 4x² + 9 + 12x
4x² + 11x + 4 = 0
Here a = 4, b = 11, c = 5
x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-11 \pm \sqrt{121-64}}{8}\)
= \(\frac{-11 \pm \sqrt{57}}{8}\)
∴ x = \(\frac{-11+\sqrt{57}}{8}\) ; x = \(\frac{-11-\sqrt{57}}{8}\)

PART – III

III. Answer any ten questions. Question No. 42 is compulsory. [10 × 5 = 50]

Question 29.
An open box is to be made from a square piece of material, 24 cm on a side, by cutting equal squares from the comers and turning up the sides as shown. Express the volume V of the box as a function of x.

Question 30.
Find the greatest number consisting of 6 digits which is exactly divisible by 24,15,36?

Question 31.
The present value of a machine is ₹40,000 and its value depreciates each year by 10%. Find the estimated value of the machine in the 6th year.

Question 32.
The sum of the digits of a three-digit number is 11. If the digits are reversed, the new number is 46 more than five times the old number. If the hundreds digit plus twice the tens digit is equal to the units digit, then find the original three digit number?

Question 33.
Find the square root of the expression \(\frac{4 x^{2}}{y^{2}}+\frac{20 x}{y}+13-\frac{30 y}{x}+\frac{9 y^{2}}{x^{2}}\)

Question 34.
If α, β are the roots of 7x² + ax + 2 = 0 and if β – α = \(\frac { -13 }{ 7 }\) . Find the values of a.

Question 35.
State and prove Angle Bisector Theorem.

Question 36.
A quadrilateral has vertices at A(-4, -2) , B(5, -1) , C(6, 5) and D(-7, 6). Show that the mid-points of its sides form a parallelogram.

Question 37.
Two ships are sailing in the sea on either side of the lighthouse. The angles of depression of two ships as observed from the top of the lighthouse are 60° and 45° respectively.
If the distance between the ships is 200 \(\left(\frac{\sqrt{3}+1}{\sqrt{3}}\right)\) meters, find the height of the light house.

Question 38.
A shuttle cock used for playing badminton has the shape of a frustum of a cone is mounted on a hemisphere. The diameters of the frustum are 5 cm and 2 cm. The height of the entire shuttle cock is 7 cm. Find its external surface area.

Question 39.
Two dice are rolled together. Find the probability of getting a doublet or sum of faces as 4.

Question 40.
Given f(x) = x – 2 ; g(x) = 3x + 5; h(x) = 2x – 3 verify that (goh) of = go (hof)

Question 41.
A 20 m deep well with inner diameter 7 m is dug and the earth from digging is evenly spread out to form a platform 22m by 14m. Find the height of the platform.

Question 42.
The mean and standard deviation of 20 items are found to be 10 and 2 respectively. At the time of checking it was found that an item 12 was wrongly entered as 8. Calculate the correct mean and standard deviation.

PART – IV

IV. Answer all the questions. [2 × 8 = 16]

Question 43.
(a) Construct a triangle similar to a given triangle PQR with its sides equal to \(\frac { 7 }{ 3 }\) of the corresponding sides of the triangle PQR (scale factor \(\frac { 7 }{ 3 }\)).

[OR]

(b) Draw a circle of diameter 6 cm from a point P, which is 8 cm away from its centre. Draw the two tangents PA and PB to the circle and measure their lengths.

Question 44.
(a) Draw the graph of y = x² – 5x – 6 and hence solve x² – 5x – 14 = 0.

[OR]

(b) Solve graphically 2x² + x – 6 = 0.

Students can download 10th Science Chapter 9 Solutions Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 9 Solutions

Samacheer Kalvi 10th Science Solutions Text Book Back Questions and Answers

I. Choose the best answer:

Question 1.
A solution is a mixture.
(a) homogeneous
(b) heterogeneous
(c) homogeneous and heterogeneous
(d) non-homogeneous
Answer:
(a) homogeneous

Question 2.
The number of components in a binary solution is ______.
(a) 2
(b) 3
(c) 4
(d) 5.
Answer:
(a) 2

Question 3.
Which of the following is the universal solvent?
(a) Acetone
(b) Benzene
(c) Water
(d) Alcohol
Answer:
(c) Water

Question 4.
A solution in which no more solute can be dissolved in a definite amount of solvent at a given temperature is called ______.
(a) Saturated solution
(b) Un saturated solution
(c) Supersaturated solution
(d) Dilute solution.
Answer:
(a) Saturated solution

Question 5.
Identify the non-aqueous solution.
(a) sodium chloride in water
(b) glucose in water
(c) copper sulphate in water
(d) sulphur in carbon-di-sulphide
Answer:
(d) sulphur in carbon-di-sulphide

Question 6.
When pressure is increased at a constant temperature the solubility of gases in liquid ______.
(a) No change
(b) increases
(c) decreases
(d) no reaction.
Answer:
(b) increases

Question 7.
Solubility of NaCl in 100 ml water is 36 g. If 25 g of salt is dissolved in 100 ml of water how much more salt is required for saturation:
(a) 12 g
(b) 11 g
(c) 16 g
(d) 20 g
Answer:
(b) 11 g

Question 8.
A 25% alcohol solution means ______.
(a) 25 ml of alcohol in. 100 ml of water
(b) 25 ml of alcohol in 25 ml of water
(c) 25 ml of alcohol in 75 ml of water
(d) 75 ml of alcohol in 25 ml of water.
Answer:
(c) 25 ml of alcohol in 75 ml of water

Question 9.
Deliquescence is due to:
(a) Strong affinity to water
(b) Less affinity to water
(c) Strong hatred to water
(d) Inertness to water
Answer:
(a) Strong affinity to water

Question 10.
Which of the following is hygroscopic in nature?
(a) ferric chloride
(b) copper sulphate pentahydrate
(c) silica gel
(d) none of the above.
Answer:
(c) silica gel

II. Fill in the blanks:

1. The component present in lesser amount, in a solution is called ……..
2. Example for liquid in solid type solution is ……….
3. Solubility is the amount of solute dissolved in ……… g of solvent.
4. Polar compounds are soluble in ……… solvents.
5. Volume percentage decreases with increases in temperature because ………

Answer:

1. solute
2. amalgam
3. 100
4. Polar
5. of expansion of liquid

III. Match the following:

Answer:
A. (iii)
B. (i)
C. (iv)
D. (ii)

IV. True or False: (If false give the correct statement):

1. Solutions which contain three components are called binary solution.
2. In a solution the component which is present in lesser amount is called solvent.
3. Sodium chloride dissolved in water forms a non-aqueous solution.
4. The molecular formula of green vitriol is MgSO₄. 7H₂O
5. When Silica gel is kept open, it absorbs moisture from the air, because it is hygroscopic in nature.

Answer:

1. False – Solutions which contain two components are called binary solution.
2. False – In a solution the component which is present in lesser amount is called solute.
3. False – Sodium chloride dissolved in water forms an aqueous solution.
4. False – The molecular formula of green vitriol is FeSO₄. 7H₂O
5. True

V. Short Answer Questions:

Question 1.
Define the term: Solution
Answer:
A solution is a homogeneous mixture of two or more substances.

Question 2.
What is mean by the binary solution?
Answer:
A solution must at least be consisting of two components. Such solutions which are made of one solute and one solvent are called binary solutions.
E.g., On adding CuSO₄ crystals to water.

Question 3.
Give an example each

1. gas in liquid;
2. solid in liquid;
3. solid in solid;
4. gas in gas.

Answer:

1. Gas in liquid – CO₂ in water
2. Solid in liquid – NaCl in water
3. Solid in solid – Alloys
4. Gas in gas – He – O₂ gas

Question 4.
What is the aqueous and non-aqueous solution? Give an example.
Answer:
Aqueous solution: The solution in which water act as a solvent is called aqueous solution. In general, ionic compounds are soluble in water and form aqueous solutions more readily than covalent compounds. E.g. Common salt in water.

Non – Aqueous solution: The solution in which any liquid, other than water act as a solvent is called non-aqueous solution. Alcohols, benzene, ethers, etc., are used as non – aqueous solvents. E.g. Sulphur dissolved in carbon disulphide.

Question 5.
Define Volume percentage.
Answer:
Volume percentage is defined as the percentage by volume of solute (in ml) present in the given volume of solution.

Question 6.
The aquatic animals live more in a cold region. Why?
Answer:
Aquatic animals live more in cold regions because the solubility of oxygen is more in cold water (at low temperature). Therefore, aquatic animals are more comfortable in cold water.

Question 7.
Define Hydrated salt.
Answer:
Ionic substances which crystallise out from their saturated aqueous solution with a definite number of molecules of water are called hydrated salts.

Question 8.
A hot saturated solution of copper sulphate forms crystals as it cools. Why?
Answer:
The capability of a solution to maintain a certain concentration of solute is temperature-dependent. When a saturated solution of copper sulphate at above room temperature is allowed to cool, the solution becomes supersaturated and in the absence of stirring or the return of the previous solution temperature, the solute starts to precipitate out. i.e., crystal formation occurs.

Question 9.
Classify the following substances into deliquescent, hygroscopic. Cone. Sulphuric acid, Copper sulphate penta hydrate, Silica gel, Calcium chloride and Gypsum salt.
Answer:

VI. Long answer questions:

Question 1.
Write notes on?

1. saturated solution
2. unsaturated solution

Answer:

1. Saturated solution: A solution in which no more solute can be dissolved in a definite amount of the solvent at a given temperature is called saturated solution, e.g. 36 g of sodium chloride in 100 g of water at 25°C forms a saturated solution.
2. Unsaturated solution: Unsaturated solution is one that contains less solute than that of the saturated solution at a given temperature, e.g. 10 g or 20 g or 30 g of Sodium chloride in 100 g of water at 25°C forms an unsaturated solution.

Question 2.
Write notes on various factors affecting solubility.
Answer:
There are three main factors which affects the solubility of a solute. They are

1. Nature of the solute and solvent
2. Temperature
3. Pressure

1. Nature of the solute and solvent : The nature of the solute and solvent plays an important role in solubility. Even though water is Universal solvent, all substances do not dissolve in water. Dissolution occurs when similarities exist between the solvent and the solute.

Ionic compounds are soluble in polar solvent like water and covalent compounds are soluble in non-polar solvents like ether, benzene, alcohol etc.

2. Effect of Temperature :
Solubility of solid in liquid : Generally solubility of a solid solute in a liquid increases with increase in temperature.
In Endothermic process : Solubility increases with increase in temperature.
In Exothermic process : Solubility decreases with increase in temperature.
Solubility of Gases in liquid : Solubility of gases in liquid decreases with increase in temperature.

3. Effect of Pressure : Effect of pressure is observed only in the case of solubility of a gas in a liquid. When the pressure is increased, the solubility of a gas in liquid increases.

Question 3.
(a) What happens when MgSO₄.7H₂O is heated? Write the appropriate equation
(b) Define solubility.
Answer:
(a) When Epsom salt MgSO₄.7H₂O crystals are gently heated, it loses seven water molecules and becomes anhydrous MgSO₄.

(b) Solubility is defined as the amount of solute in grams that can be dissolved in 100 g of the solvent to form its saturated solution at a given temperature and pressure.

Question 4.
In what way hygroscopic substances differ from deliquescent substances.
Answer:

Question 5.
A solution is prepared by dissolving 45 g of sugar in 180 g of water. Calculate the mass percentage of solute.
Answer:
Mass of the solute (sugar) = 45 g
Mass of the solvent (Water) = 180 g
Formula:
Mass percentage of solute (sugar)

The mass percentage of solute = 20%

Question 6.
3.5 litres of ethanol is present in 15 litres of aqueous solution of ethanol. Calculate volume percent of ethanol solution.
Answer:
Volume of ethanol = 3.5 lit = 3500 ml
Volume of water = 15 lit = 15000 ml
Formula:

The volume percentage of ethanol solution = 18.92

VII. HOT Questions

Question 1.
Vinu dissolves 50 g of sugar in 250 ml of hot water, Sarath dissolves 50 g of same sugar in 250 ml of cold water. Who will get a faster dissolution of sugar? and Why?
Answer:
Vinu will get a faster dissolution of sugar. Because generally solubility of a solid solute in a liquid solvent increases with increase in temperature. Therefore Vinu dissolves 50 g of sugar in 250 ml of hot water than Sarath dissolves 50 g of sugar in 250 ml of cold water.

Question 2.
‘A’ is a blue coloured crystalline salt. On heating it loses blue colour and to give ‘B’ When water is added, ‘B’ gives back to ‘A’. Identify A and B, write the equation.
Answer:
Since ‘A’ is a blue coloured crystalline salt, it is CuSO₄. 5H₂O (Blue vitriol). On heating it loses all five water molecules and becomes colourless anhydrous CuSO₄.

When water is added ‘B’ gives back A.

Question 3.
Will the cool drinks give more fizz at top of the hills or at the foot? Explain.
Answer:
At hilltops, the temperature will become less and pressure also decreases. Because temperature and pressure are directly proportional to each other. At low-pressure carbonate, cool drinks will give less fizz and give more fizz at the foot.

Samacheer Kalvi 10th Science Solutions Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
The dissolution of sugar and salt in water results in a solution.
(a) Binary
(b) Ternary
(c) Quaternary
(d) Saturated
Answer:
(b) Ternary

Question 2.
In a solution, the component which is present in a lesser amount is called ______.
(a) solvent
(b) dissolution
(c) solute
(d) mole.
Answer:
(c) solute

Question 3.
The supersaturated solution of NaCl in 100 g of water at 25°C contains:
(a) 40 g of NaCl
(b) 10 g of NaCl
(c) 20 g of NaCl
(d) 30 g of NaCl
Answer:
(a) 40 g of NaCl

Question 4.
How many component(s) present in binary solution?
(a) 1
(b) 2
(c) 3
(d) 4.
Answer:
(b) 2

Question 5.
Formalin is an aqueous solution of:
(a) formic acid
(b) ammonia
(c) formaldehyde
(d) carbon tetrachloride
Answer:
(c) formaldehyde

Question 6.
The effect of pressure on the solubility of a gas in liquids is given by:
(a) Boyle’s Law
(b) Charle’s Law
(c) Henry’s Law
(d) Avogadro’s Law
Answer:
(c) Henry’s Law

Question 7.
Which one of the following is an example of an aqueous solution?
(a) Sugar in water
(b) Sulphur in carbon disulphide
(c) Iodine dissolved in carbon tetrachloride
(d) Benzoic acid in ethers.
Answer:
(a) Sugar in water

Question 8.
The type of solution when CO₂ is dissolved in water:
(a) solid/liquid
(b) liquid in liquid
(c) gas in liquid
(d) liquid in solid
Answer:
(c) gas in liquid

Question 9.
Tin amalgam is an example of ……… solution.
(a) solid in solid
(b) liquid in solid
(c) solid in liquid
(d) liquid in liquid
Answer:
(b) liquid in solid

Question 10.
In which case solubility decreases with increase in temperature?
(a) Endothermic process
(b) Exothermic process
(c) Both (a) and (b)
(d) None of these.
Answer:
(b) Exothermic process

Question 11.
Fat is soluble in:
(a) water
(b) alcohol
(c) CCl₄
(d) ether
Answer:
(d) ether

Question 12.
The deliquescent substance among the following is:
(a) con.H₂SO₄
(b) P₂O₅
(c) CaCl₂
(d) SiO₂
Answer:
(c) CaCl₂

Question 13.
Mass percentage is expressed as ______.
(a) v/v
(b) w/w
(c) v/w
(d) w/v.
Answer:
(b) w/w

Question 14.
Hygroscopic substances are used as ……… agents.
(a) foaming
(b) drying
(c) oxidising
(d) reducing
Answer:
(b) drying

Question 15.
The molecular formula of Epsom salt is ______.
(a) CuSO₄.5H₂O
(b) FeSO₄.7H₂O
(c) MgSO₄.7H₂O
(d) ZnSO₄.7H₂O.
Answer:
(c) MgSO₄.7H₂O

II. Fill in the blanks:

1. A true solution is a ……… mixture of solute and solvent.
2. Soil cannot store more nitrogen than it can hold because soil is said to be in a state of ………
3. In the dissolution of NaOH in water, the solubility …….. with increase in temperature.
4. Aquatic animals are more comfortable in cold water because as the temperature is less the solubility of dissolved oxygen ………
5. Hydrated salts contain ……… of crystallization.
6. He-O₂ mixture is a binary solution of …….. in ………. solution.
7. The solvent used for dissolving Sulphur is ……….
8. The solubility of NaOH at 25°C is ……….
9. According to Henry’s Law, the solubility of a gas in liquid is ………. proportional to the pressure of the gas over the solution at definite temperature.
10. Anhydrous Calcium chloride is a ………. substance.
11. ……… substances absorb enough water from the atmosphere and get completely dissolved.
12. When 90g of sodium bromide is dissolved in 100 g of water at 25°C it forms a ………. solution.
13. ………. is an example of a binary solution with liquid in Gas.
14. Air and sea water are important ……… solution.
15. A quaternary solution contains ……….. components.
16. The primary factor which determines the characteristic of a solution is ………..
Answer:
1. Homogeneous
2. saturation
3. decreases
4. increases
5. water
6. Gas, Gas
7. CS₂ (or) Carbon disulphide
8. 80 g
9. directly
10. Hygroscopic
11. deliquescent
12. Unsaturated
13. Cloud
14. Homogeneous
15. four
16. Physical state

III. Match the following

Question 1.
Match the column I with column II.

Answer:
A. (iv)
B. (iii)
C. (v)
D. (ii)
E. (i)

Question 2.
Match the column I with column II.

Answer:
A. (iii)
B. (iv)
C. (v)
D. (ii)
E. (i)

Question 3.
Match the column I with column II.

Answer:
A. (v)
B. (iii)
C. (ii)
D. (i)
E. (iv)

Question 4.
Match the column I with column II.

Answer:
A. (iii)
B. (iv)
C. (v)
D. (i)
E. (ii)

Question 5.
Match the column I with column II.

Answer:
A. (iv)
B. (iii)
C. (i)
D. (v)
E. (ii)

IV. True or False: (If false give the correct statement)

1. In an aqueous solution of copper sulphate, the solvent is copper sulphate.
2. A solution containing sugar and salt in water is a binary solution.
3. An example of a solid solution is alloy.
4. The difference between concentrated and dilute solution can be observed by means of colour (or) density.
5. A saturated solution contains 91 g of Glucose in 100 g of water at 25°C.
6. Fat is dissolved in the aqueous solvent ether.
7. The solubility of a gas in a liquid is inversely proportional to the pressure of the gas at a definite temperature.
8. Mass percentage of a solution is expressed as .
9. The white vitriol is represented by the formula ZnSO₄ . 7H₂O.
10. Ferric chloride is a Hygroscopic substance.
Answer:
1. False – In an aqueous solution of copper sulphate, the solvent is water.
2. False – A solution containing sugar and salt in water is a ternary solution.
3. True
4. True
5. True
6. False – Fat is dissolved in the non-aqueous solvent ether.
7. False – The solubility of a gas in a liquid is directly proportional to the pressure of the gas at a definite temperature.
8. True
9. True
10. False – Ferric chloride is a deliquescent substance.

V. Short answer questions:

Question 1.
(i) Which gas is dissolved in soft drinks?
(ii) What will you do to increase the solubility of this gas?
Answer:
(i) Carbon-di-oxide (CO₂) is dissolved in soft drinks.
(ii) An increase in pressure will increase the solubility of CO₂ gas.

Question 2.
Identify the type of binary solution given below.
Answer:

1. Alloys
2. Amalgam
3. Ethyl alcohol in water
4. Aerated drinks

Answer:

1. Solid in solid
2. liquid in solid
3. liquid in liquid
4. Gas in liquid

Question 3.
Explain why Nitrogen in soil is called a saturated solution in nature?
Answer:
Nitrogen in soil is an example of a saturated solution in nature. Soil cannot store more Nitrogen than it can hold.

Question 4.
Define Mass percentage.
Answer:
Mass percentage of a solution is defined as the percentage by mass of the solute present in the solution.

Question 5.
Define the term Molarity (M).
Answer:

Question 6.
Define the term Molality (m).
Answer:

Question 7.
Define the supersaturated solution.
Answer:
A supersaturated solution is one that contains more solute than the saturated solution at a given temperature.
E.g. 40 g of sodium chloride in 100 g of water at 25°C.

Question 8.
Justify the following statements with an explanation.
(i) Solubility of NH₄Cl increases with increase in temperature.
Answer:
Solubility of NH₄Cl increases with increase in temperature because it is an endothermic process.

(ii) Solubility of NaOH decreases with increase in temperature.
Answer:
Solubility of NaOH decreases with increase in temperature because it is an exothermic process.

Question 9.
Calculate the molarity of a solution containing 4 g of NaOH in 500 ml of water.
Answer:
Mass of NaOH = 4 g
Volume of solution = 500 ml

= 0.1 × 2
= 0.2 M

Question 10.
Calculate the molality of a solution containing 3 g of urea (molecular mass = 60) in 750 g of water.
Answer:
Mass of urea (solute) = 3 g
Mass of water (solvent) = 750 g
Formula:

Question 11.
Define dissolution.
Answer:
The process of uniform distribution of solute into solvent is called dissolution.

VI. Long answer questions:

Question 1.
Answer the blanks given in the table.
Answer:

Question 2.
Write a note on the type of solution based on the type of solvent.
Answer:
(i) Aqueous solution : The solution in which water acts as a solvent is called aqueous solution. In general, ionic compounds are soluble in water and form aqueous solutions more readily than covalent compounds.
Eg: Common salt in water, Sugar in water, Copper sulphate in water etc..

(ii) Non-Aqueous solution : The solution in which any liquid, otter than water, acts as a solvent is called non-aqueous solution. Solvent other than water is referred to as non-aqueous solvent. Generally, alcohols, benzene, ethers, carbon disulphide, acetone, etc., are used as non- aqueous solvents.
Eg: Sulphur dissolved in carbon disulphide, Iodine dissolved in carbon tetrachloride.

Question 3.
Justify the following statements with an explanation.

1. The solubility of calcium oxide decreases with increase in temperature,
2. What happens to the solubility in the exothermic process with regard to temperature?
3. In the endothermic process, solubility increases with increase in temperature.
4. At a given temperature, an increase in pressure increases the solubility of the gas

Answer:

1. In an exothermic process, the solubility decreases. When calcium oxide dissolves in water, an exothermic reaction takes place, and so the solubility of calcium oxide decreases
2. In an exothermic process, the solubility decreases with the increase in temperature, as there is already an evolution of heat and it is observed.
3. In an endothermic process, the solubility increases. The solubility of KNO₃ in water is an endothermic reaction and so solubility increases with the increase of temperature.
4. At a given temperature, an increase in pressure increases the solubility of gas according to Henry’s law. e.g. (CO₂ in soft drinks)

VII. Hot Questions.

Question 1.
50 ml tincture of benzoin, antiseptic solution contains 10 ml of benzoin. Calculate the volume of percentage of benzoin.
Answer:
Volume of the solute, Benzoin = 10 ml
Volume of the solution, tincture of benzoin = 50 ml

= 20% (v/v)

Question 2.
Neomycin, the antibiotic cream contains 300 mg of neomycin sulphate the active ingredient in 30 g of ointment base. Calculate the mass percentage of neomycin.
Answer:
Mass of neomycin sulphate(solute) = 300 mg
Mass of the ointment (solution) = 30 g
Formula:

VIII. Numerical problems:

Question 1.
Calculate the molality of the solution containing 18 g of Glucose (Molecular mass 180) in 2 kg of water.
Answer:
Mass of Glucose = 18 g
Molecular mass of Glucose = 180

= 0. 05 m

Question 2.
Calculate the molarity of a solution containing 5.85 g of sodium chloride in 500 ml of the water. (Molecular mass = 58.5)
Answer:
Mass of the solute = 5.85 g
Volume of the solution = 500
No. of moles of NaCl = \(\frac{5.85}{58.5}\) = 0.1

= \(\frac{0.1}{500}\) × 1000 = 0.2 M

Students can download 10th Science Chapter 8 Periodic Classification of Elements Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 8 Periodic Classification of Elements

Samacheer Kalvi 10th Science Periodic Classification of Elements Text Book Back Questions and Answers

I. Choose the best answer:

Question 1.
The number of periods and groups in the periodic table are:
(a) 6, 16
(b) 7, 17
(c) 8, 18
(d) 7, 18
Answer:
(d) 7, 18

Question 2.
The basis of modem periodic law is ____.
(a) atomic number
(b) atomic mass
(c) isotopic mass
(d) number of neutrons.
Answer:
(a) atomic number

Question 3.
……….. group contains the member of the halogen family.
(a) 17th
(b) 15th
(c) 18th
(d) 16th
Answer:
(a) 17th

Question 4.
_______ is a relative periodic property.
(a) atomic radii
(b) ionic radii
(c) electron affinity
(d) electronegativity.
Answer:
(b) ionic radii

Question 5.
Chemical formula of rust is:
(a) Fe0.xH₂O
(b) Fe04.xH₂O
(c) Fe₂O₃. xH₂O
(d) FeO
Answer:
(c) Fe₂O₃. xH₂O

Question 6.
In the aluminothermic process the role of Al is:
(a) oxidizing agent
(b) reducing agent
(c) hydrogenating agent
(d) sulphurising agent
Answer:
(b) reducing agent

Question 7.
The process of coating the surface of the metal with a thin layer of zinc is called ____.
(a) painting
(b) thinning
(c) galvanization
(d) electroplating.
Answer:
(c) galvanization

Question 8.
Which of the following inert gas has electrons in the outermost shell?
(a) He
(b) Ne
(c) Ar
(d) Kr
Answer:
(a) He

Question 9.
Neon shows zero electron affinity due to ____.
(a) stable arrangement of neutrons
(b) stable configuration of electrons
(c) reduced size
(d) increased density.
Answer:
(b) stable configuration of electrons

Question 10.
……….. is an important metal to form amalgam.
(a) Ag
(b) Hg
(c) Mg
(d) Al
Answer:
(b) Hg

II. Fill in the blanks:

1. If the electronegativity difference between two bonded atoms in a molecule is greater than 1.7, the nature of bonding is ………..
2. …………. is the longest period in the periodical table.
3. ………… forms the basis of modern periodic table.
4. If the distance between two Cl atoms in Cl₂ molecule is 1.98 Å, then the radius of Cl atom is ………..
5. Among the given species A^– A⁺, and A, the smallest one in size is ……….
6. The scientist who propounded the modern periodic law is …………
7. Across the period, ionic radii ………… (increases,decreases).
8. ……….. and ………… are called inner transition elements.
9. The chief ore of Aluminium is ………….
10. The chemical name of rust is ………….
Answer:
1. ionic
2. 6th (sixth) period
3. Atomic number
4. 0.99 Å
5. A⁺
6. Dimitri Mendeleev
7. decreases
8. Lanthanides, Actinides
9. bauxite
10. hydrated ferric oxide

III. Match the following:

Answer:
A. (ii)
B. (v)
C. (iv)
D. (iii)
E. (i)

IV. True or False: (If false give the correct statement)

1. Moseley’s periodic table is based on atomic mass.
2. Ionic radius increases across the period from left to right.
3. All ores are minerals; but all minerals cannot be called as ores.
4. Aluminium wires are used as electric cables due to their silvery white colour.
5. An alloy is a heterogenous mixture of metals.
Answer:
1. False – Moseley’s periodic table is based on atomic number.
2. True
3. True
4. False – Aluminium wires are used as electric cables because it is a good conductor of heat and electricity.
5. False – An alloy is an homogeneous mixture of metals.

V. Assertion and Reason:

Answer the following questions using the data given below:
Question 1.
Assertion: The nature of bond in HF molecule is ionic.
Reason: The electronegativity difference between H and F is 1.9.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains the Assertion.

Question 2.
Assertion: Magnesium is used to protect steel from rusting.
Reason: Magnesium is more reactive than iron.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains the Assertion.

Question 3.
Assertion: An uncleaned copper vessel is covered with greenish layer. Reason: copper is not attacked by alkali.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.

VI. Short answer questions:

Question 1.
A is a reddish brown metal, which combines with O₂ at < 1370 K gives B, a black coloured compound. At a temperature > 1370 K, A gives C which is red in colour. Find A, B and C with reaction.
Answer:
(A) is a reddish brown metal – Copper

A – Copper; B – Cupric oxide; C – Cuprous oxide.

Question 2.
A is a silvery white metal. A combines with O₂ to form B at 800°C, the alloy of A is used in making the aircraft. Find A and B.
Answer:
A – Silvery white metal – Aluminium

The alloys of aluminium, Duralumin and Magnalium are used in making the aircraft.
A – Aluminium; B – Aluminium oxide.

Question 3.
What is rust? Give the equation for the formation of rust.
Answer:
When iron is exposed to moist air, it forms a layer of brown hydrated ferric oxide on its surface. This compound is known as rust and the phenomenon of formation of rust is known as rusting.
4Fe + 3O₂ + xH₂O → 2Fe₂O₃. xH₂O (Rust).

Question 4.
State two conditions necessary for rusting of iron.
Answer:
(i) The presence of water and oxygen is essential for the rusting of iron.
(ii) Impurities in the iron, the presence of water vapour, acids, salts and CO₂ speeds up rusting.

VII. Long answer questions:

Question 1.
(a) State the reason for addition of caustic alkali to bauxite ore during purification of bauxite.
Answer:
Caustic alkali is added to bauxite, to dissolve bauxite ore and obtain a solution of sodium aluminate.

(b) Along with cryolite and alumina, another substance is added to the electrolyte mixture. Name the substance and give one reason for the addition.
Answer:
CaF₂ (Fluorspar) is added along with cryolite and alumina. It is added to reduce the high melting point of the electrolyte.

Question 2.
The electronic configuration of metal A is 2, 8, 18, 1.
The metal A when exposed to air and moisture forms B a green layered compound. A with con. H₂SO₄ forms C and D along with water. D is a gaseous compound. Find A, B, C and D.
Answer:
Metal (A) with electronic configuration- 2, 8, 18, 1 is copper.
2Cu + O₂ + CO₂ + H₂O → CuCO₃. Cu(OH)₂ (B)
Copper carbonate (Green layer)

(A) – Copper (Cu)
(B) – Copper Carbonate (CuCO₃. Cu(OH)₂)
(C) – Copper Sulphate (CuSO₄)
(D) – Sulphur dioxide (SO₂)

Question 3.
Explain the smelting process.
Answer:
The roasted ore of copper is mixed with powdered coke and sand and is heated in a blast furnace to obtain matte (Cu₂S + FeS) and slag. The slag is removed as waste.
2 FeS + 3O₂ → 2 FeO + 2 SO₂
2 Cu₂S + 3O₂ → 2 Cu₂O + 2SO₂
Cu₂O + FeS → Cu₂S + FeO
FeO + SiO₂ → FeSiO₂ (slag)

VIII. HOT questions:

Question 1.
Metal A belongs to period 3 and group 13. A in red hot condition reacts with steam to form B. A with strong alkali forms C. Find A, B and C with reactions.
Answer:
Metal A belongs to Period 3 and Group 13. So metal ‘A’ is aluminium.
(A) in red hot condition reacts with steam to form ‘B’.

‘A’ with strong alkali forms ‘C’

(A) – Aluminium
(B) – Aluminium oxide
(C) – Sodium meta aluminate

Question 2.
Name the acid that renders aluminium passive. Why?
Answer:
Dilute or concentrated nitric acid (HNO₃) renders aluminium passive. Because nitric acid does not attack aluminium but it renders aluminium passive due to the formation of an oxide film on its surface.

Question 3.
(a) Identify the bond between H and F in HF molecule.
Answer:
Ionic, because the electronegativity difference is more than 1.7.

(b) What property forms the basis of identification?
Answer:
Electronegativity.

(c) How does the property vary in periods and in groups?
Answer:
In a period, from left to right the electronegativity increases because of the increase in the nuclear charge.
In a Group, from top to bottom, the electronegativity decreases because of the increase in size of the elements.

Samacheer Kalvi 10th Science Periodic Classification of Elements Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
The shortest period in the periodic table contains elements.
(a) 18
(b) 8
(c) 2
(d) 32
Answer:
(c) 2

Question 2.
Group number of carbon family is _____.
(a) 13
(b) 15
(c) 17
(d) 14.
Answer:
(d) 14.

Question 3.
The ore forming elements, chalcogens are present in ……… group of the modern periodic table.
(a) 18th
(b) 1st
(c) 2nd
(d) 16th
Answer:
(d) 16th

Question 4.
Valency of all the alkali metals is _____.
(a) 1
(b) 2
(c) 3
(d) 4.
Answer:
(a) 1

Question 5.
The largest atom in the 2nd period of the periodic table is:
(a) Li
(b) Be
(c) F
(d) Ne
Answer:
(a) Li

Question 6.
The covalent radii of Hydrogen, if the distance between the Hydrogen nuclei of the molecule is 0.74 Å is:
(a) 1.58 Å
(b) \(\frac{0.74}{4}\) Å
(c) 0.37 Å
(d) 0.74 Å
Answer:
(c) 0.37 Å

Question 7.
Pick out the correct ionic radii in increasing order for the following species – Na, Cl, Na⁺, Cl^– _____.
(a) Na > Cl > Na⁺ > Cl^–
(b) Cl > Na > Na⁺ > Cl^–
(c) Cl^– > Na > Na⁺ > Cl
(d) Cl < Na⁺ < Cl^– < Na.
Answer:
(d) Cl < Na⁺ < Cl^– < Na.
Hint:
Na = 186 pm,
Cl = 91 pm,
Na⁺ = 116 pm,
Cl^– = 167 pm.

Question 8.
In the third period, the first ionization potential is of the order:
(a) Na > Al > Mg > Si > P
(b) Mg > Na > Si > P > Al
(c) Na < Al < Mg < Si < P
(d) Na < Al < Mg < Si < P
Answer:
(c) Na < Al < Mg < Si < P

Question 9.
Which one of the following is the least electronegative element?
(a) Bromine
(b) Chlorine
(c) Iodine
(d) Hydrogen
Answer:
(d) Hydrogen

Question 10.
Which is a widely used a scale to determine the electronegativity?
(a) Pauling scale
(b) Moseley scale
(c) Mendeleev scale
(d) none of these.
Answer:
(a) Pauling scale

Question 11.
Which one of the following orders of ionic radii is correct?
(a) H^– > H⁺ > H
(b) Na⁺ > F^– > O^2-
(c) F > O^2- > Na⁺
(d) None of these
Answer:
(d) None of these

Question 12.
The percentage of carbon in Pig iron is:
(a) < 0.25%
(b) 0.25 – 2%
(c) 2 – 4.5%
(d) > 5%
Answer:
(c) 2 – 4.5%

Question 13.
The chemical formula of clay is _____.
(a) Al₂O₃
(b) Al₂O₃.2H₂O
(c) Al₂O₃. 2SiO₂.2H₂O
(d) Al₂O₃. 2SiO₂.H₂O.
Answer:
(c) Al₂O₃. 2SiO₂.2H₂O

Question 14.
The temperature in the combustion zone is maintained at:
(a) 1500°C
(b) 400°C
(c) 1000°C
(d) 1380°C
Answer:
(a) 1500°C

Question 15.
Oil used in Froth floatation method is _____.
(a) pine oil
(b) natural oil
(c) crude oil
(d) Synthetic oil.
Answer:
(a) pine oil

Question 16.
The first most abundant metal present in the Earth crust is:
(a) Iron
(b) Aluminium
(c) Zinc
(d) Copper
Answer:
(b) Aluminium

Question 17.
……….. metal is used for making calorimeters.
(a) Copper
(b) Tin
(c) Mercury
(d) Iron
Answer:
(a) Copper

Question 18.
More reactive metal is _____.
(a) Zn
(b) Fe
(c) Ag
(d) Na.
Answer:
(d) Na.

Question 19.
The chief ore of Iron is:
(a) Magnesite
(b) Galena
(c) Cinnabar
(d) Haematite
Answer:
(d) Haematite

Question 20.
The metal which melts at room temperature is:
(a) Zinc
(b) Lead
(c) Gallium
(d) Tin
Answer:
(c) Gallium

Question 21.
Conversion of bauxite into alumina is _____.
(a) Hall’s process
(b) Alumino thermic process
(c) Baeyer’s process
(d) Bessemerisation process.
Answer:
(c) Baeyer’s process

Question 22.
………. metal can be cut with knife.
(a) Potassium
(b) Gallium
(c) Mercury
(d) Gold
Answer:
(a) Potassium

Question 23.
………. is not a good conductor of heat and electricity.
(a) Silver
(b) Tungsten
(c) Copper
(d) Aluminium
Answer:
(b) Tungsten

Question 24.
Electrolyte used in Hall’s process ______.
(a) Pure alumina + molten cryolite + fluorspar
(b) Pure alumina + molten bauxite + fluorspar
(c) Pure bauxite + molten cryolite + fluorspar
(d) Pure bauxite + molten Haematite + fluorspar.
Answer:
(a) Pure alumina + molten cryolite + fluorspar

Question 25.
The foaming agent used for froth floatation process is:
(a) Coconut oil
(b) Pine oil
(c) Sodium chloride
(d) Groundnut oil
Answer:
(b) Pine oil

Question 26.
Three elements A, B and C are having the electronic configuration Is² 2s¹, Is² 2s² and Is² 2s² 2p¹ respectively. Which element will have the lowest ionization energy?
(a) A
(b) B
(c) C
(d) B and C
Answer:
(a) A

Question 27.
Metal used in household utensils is ______.
(a) Al
(b) Co
(c) Fe
(d) Na.
Answer:
(a) Al

Question 28.
Which one of the following pair is a metalloid?
(a) Na and K
(b) F and Cl
(c) Cu and Hg
(d) Si and Ge
Answer:
(d) Si and Ge

Question 29.
The highly metallic element will have the configuration of:
(a) 2, 8, 7
(b) 2, 8, 8, 5
(c) 2, 8, 8, 1
(d) 2, 8, 2
Answer:
(c) 2, 8, 8, 1

Question 30.
The metal used in electroplating is ______.
(a) Cu
(b) Al
(c) Fe
(d) Co.
Answer:
(a) Cu

Question 31.
The flux which is used when the gangue present in the ore is acidic:
(a) Silica
(b) Calcium oxide
(c) Calcium silicate
(d) Cuprous sulphide
Answer:
(b) Calcium oxide

Question 32.
Matte is a mixture of:
(a) Cu₂O + Cu₂S
(b) Cu₂O + FeS
(c) Cu₂S + FeS
(d) Cu₂O + PbS
Answer:
(c) Cu₂S + FeS

Question 33.
Fe reacts with dilute nitric acid in cold condition to give ______.
(a) Ferrous nitride
(b) Ferrous nitrate
(c) Ferric nitride
(d) Ferric nitrate.
Answer:
(b) Ferrous nitrate

Question 34.
In the brass alloy, which is solvent?
(a) Zn
(b) Co
(c) Ag
(d) Cu.
Answer:
(d) Cu.

II. Fill in the blanks:

1. The major component of the matte is ………….
2. The modern periodic table is based on ………..
3. The valency of alkali metals is …………
4. The unreactive elements are present in group ………..
5. In the 2nd period, the smallest atom is ……….
6. The size of a cation is ………… than the neutral atom.
7. ……….. is the unit of ionization energy.
8. The ionization energy ……… down the group in the periodic table.
9. The electron affinities of noble gases are …………
10. ………. is the process of extracting the ore from the Earth’s crust.
11. Galena is the ore of …………..
12. The silvery white metal which is a good conductor of heat and electricity is …………
13. The slag formed during Bessemerisation process is ………….
14. Blister copper contains ………. percentage of copper.
15. Haematite ore is concentrated by ……….. washing.
Answer:
1. Cu₂S
2. atomic number
3. one
4. 18
5. Neon
6. smaller
7. KJ/mol
8. decreases
9. zero
10. Mining
11. lead
12. aluminium
13. Iron silicate or FeSiO₃
14. 98%
15. hydraulic

III. Match the following:

Question 1.
Match the column I with column II.

Answer:
A. (iv)
B. (v)
C. (i)
D. (ii)
E. (iii)

Question 2.
Match the column I with column II.

Answer:
A. (ii)
B. (iv)
C. (v)
D. (iii)
E. (i)

Question 3.
Match the column I with column II.

Answer:
A. (iii)
B. (iv)
C. (v)
D. (i)
E. (ii)

Question 4.
Match the column I with column II.

Answer:
A. (v)
B. (iv)
C. (ii)
D. (iii)
E. (i)

IV. True or false. (If false give the correct statement)

1. Alkali metals are generally extracted by the electrolysis of their ores in fused state.
2. Every mineral is an ore but every ore is not a mineral.
3. Slag is a product formed during smelting by combination of flux and impurities.
4. Reactive metals occur in native state.
5. Malachite is a sulphide ore of copper.
6. Lanthanides are present in the 6th group of the periodic table.
7. Atomic radius increases as we go across the period due to increase in size.
8. As the positive charge increases, the size of the cation decreases.
9. If the difference in electronegativity is greater than 1.7, the bond is considered to be covalent.
10. Siderite is the carbonate ore of calcium.
Answer:
1.True
2. True
3. True
4. False – Reactive metals always occur in the combined state.
5. False – Malachite is the carbonate ore of copper.
6. False – Lanthanides are present in the 6th period of the periodic table.
7. False – Atomic radius increases as we go across the period due to decrease in size.
8. True
9. False – If the difference in electronegativity is greater than 1.7, the bond is considered to be ionic.
10. False – Siderite is the carbonate ore of Iron.

V. Assertion and Reason:

Answer the following questions using the data given below:
Question 1.
Assertion: Zinc blende is concentrated by Froth floatation process.
Reason: Zinc blende is a sulphide ore.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains the Assertion.

Question 2.
Assertion: In thermite welding, aluminium powder and Fe₂O₃ are used.
Reason: Aluminium powder is a strong reducing agent.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains the Assertion.

Question 3.
Assertion: To design the body of an aircraft, aluminium alloys are used.
Reason: Aluminium becomes passive when it is treated with dil or con.HNO₃
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.

Question 4.
Assertion: Tinstone and the impurity wolframite are seperated by magnetic separation.
Reason: Tinstone is magnetic and wolframite is non-magnetic in nature.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains the Assertion.

Question 5.
Assertion: Bauxite is purified by leaching.
Reason: Bauxite undergoes thermal decomposition.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(b) Assertion is correct, Reason is wrong.

VI. Short answer questions:

Question 1.
State the modern periodic law.
Answer:
The physical and chemical properties of the elements are the periodic function of their atomic number.

Question 2.
‘X’ is a silvery white metal. X reacts with O₂ to form Y. The same compound is obtained from the metal on reaction with steam with the liberation of hydrogen gas. Identify X and Y.
Answer:
(i) Silvery white metal ‘X’ is Aluminium.
(ii) It reacts with O₂ to form ‘Y’

(iii) Y can also be obtained on reaction with steam with the liberation of H₂.

Question 3.
Write any four characteristics of periods.
Answer:

• In a period, the electrons are filled in the same valence shell of all elements.
• As the electronic configuration changes along the period, the chemical properties of the elements also change.
• The atomic size of the elements in a period decreases from left to right
• In a period, die metallic character of the element decreases, while their non-metallic character increases.

Question 4.
Write the Principle of Hydraulic washing.
Answer:
The difference in the densities or specific gravities of the ore and the gangue is the main principle behind this method.

Question 5.
What are coinage metals?
Answer:
Copper, silver and gold are called coinage metals, as they are used in making coins and jewellery.

Question 6.
How will you separate tinstone from wolframite?
Answer:
Magnetic separation method. Tinstone is magnetic in nature.
Method: The crushed ore is placed over a conveyer belt which rotates around two metal wheels, one of which is magnetic. The magnetic particles are attracted to the magnetic wheel and fall separately apart from the non¬magnetic particles.

Question 7.
What are ores?
Answer:
The mineral from which a metal can be readily and economically extracted on a large scale is said to be ore.
eg. Bauxite Al₂O₃.2H₂O is the ore of Aluminium

Question 8.
Define electronegativity.
Answer:
It is the tendency of an element in a covalent bond to attract the shared pair of electrons towards itself. It is a relative property.

Question 9.
In what period and group will an element with z = 118 will be present?
Answer:
Elements with z = 118 will be present in Period number ‘7’ and Group number 18.

Question 10.
Why flux is added during metallurgy?
Answer:
Flux is the substance added to the ore to reduce the fusion temperature and to remove impurities.
e.g. CaO, SiO₂

Question 11.
State the trends in the electronegativity in a Group and period.
Answer:
In a Group: Electronegativity decreases in a group because of the increased number of energy levels.
In a Period: The electronegativity increases because the increase in the nuclear charge.

Question 12.
Write a note about smelting.
Answer:
Smelting is a process of reducing the roasted metallic oxide to metal in a molten condition. In this process, impurities are removed by the addition of flux as slag.

Question 13.
Write the formula of the ores of Aluminium.
Answer:

Question 14.
Explain the action of Aluminium with air.
Answer:
On heating at 800°C, aluminium bums in the air very brightly forming its oxide and nitride.
4Al + 3O₂ → 2Al₂O₃ (Aluminium oxide)
2Al + N₂ → 2AlN (Aluminium nitride).

Question 15.
What happen when Aluminium reacts with steam?
Answer:
When steam is passed over red hot aluminium, H₂ gas is evolved.

Question 16.
Write the reaction of Aluminium with Sodium hydroxide?
Answer:

Question 17.
Explain the electrolytic refining of copper.
Answer:
Cathode: A thin plate of pure copper metal.
Anode: A block of impure copper metal.
Electrolyte: Copper sulphate solution + dilute H₂SO₄
When an electric current is passed through the electrolytic solution, pure copper gets deposited at the cathode and the impurities are settled at the bottom of the anode as anode mud.

Question 18.
Mention the uses of Aluminium.
Answer:
Aluminium is used in

1. household utensils
2. electrical cable industry
3. making aeroplanes and other industrial machine parts.

Question 19.
What are the methods employed to make an alloy?
Answer:

1. By fusing the metals together. Eg: Brass is made by melting zinc and copper.
2. By compressing finely divided metals. Eg: wood mexai.

Question 20.
Write the components of wood metal.
Answer:
Wood metal is an alloy of Lead, Tin, Bismuth and Cadmium.

Question 21.
What are the uses of copper?
Answer:

• Copper is used in manufacturing electric cables and other electric appliances.
• Copper is used for making utensils, containers, calorimeters and coins.
• Copper is used in electroplating.
• Copper is alloyed with gold and silver for making coins and jewels.

Question 22.
Give example for non-ferrous copper and aluminium alloys. Non-ferrous copper alloys: Brass (Cu, Zn), Bronze (Cu, Sn)
Answer:
Non-ferrous aluminium alloys: Duralumin (Al, Mg, Cu, Mn), Magnalium (Al, Mg)

Question 23.
How is rust formed?
Answer:
When iron is exposed to moist air, it forms a layer of brown hydrated Ferric oxide on its surface. This compound is known as rust.
4Fe + 3O₂ + xH₂O → 2Fe₂O₃. xH₂O (Rust).

Question 24.
Why are the alloys prepared?
Answer:

1. To modify appearance and colour.
2. To modify chemical activity.
3. To lower the melting point.
4. To increase hardness and tensile strength.
5. To increase resistance to electricity.

Question 25.
Define corrosion.
Answer:
Corrosion is the gradual destruction of metals by chemical or electrochemical reaction with the environment.

Question 26.
What are alloys? How are they prepared?
Answer:

• An alloy is a homogeneous mixture of a metal with other metals or with non-metals that are fused together. e.g. Brass is an alloy of zinc (solute) in copper (solvent)
• Alloys are prepared by fusing the metals together.
• Alloys are prepared by compressing finely divided metals one over the other.

Question 27.
Which is known as Wet corrosion or Electrochemical corrosion?
Answer:
The corrosive action in the presence of moisture is called wet corrosion. It occurs as a result of electrochemical reaction of metal with water or aqueous solution of salt or acids or bases.

Question 28.
Write a note on Cathodic protection.
Answer:
It is the method of controlling corrosion of a metal surface protected is coated with the metal which is easily corrodible. The easily corrodible metal is called Sacrificial metal to act as anode ensuring cathodic protection.

Question 29.
What are the methods used to prevent corrosion?
Answer:
Corrosion of metals is prevented

• by coating with paints
• by coating with oil and grease
• by alloying with other metals
• by the process of galvanization
• by electroplating
• by sacrificial protection

Question 30.
A reddish brown metal ‘A’ reacts with dil.HCl in the presence of O₂ and forms the compound ‘B’. ‘B’ can also be prepared by heating the metal A with Cl₂. Identify A and B.
Answer:
Reddish brown metal ‘A’ is copper.
(A) reacts with dil.HCl in the presence of O₂ and forms CuCl₂ which is ‘B’.

(B) can also prepared by the action of Cl₂.

Question 31.
Write the uses of copper.
Answer:

1. It is extensively used in manufacturing electric cables and other electric appliances.
2. It is used for making utensils, containers, calorimeters and coins.
3. It is used in electroplating.
4. It is alloyed with gold and silver for making coins and jewels.

Question 32.
Write the name and formula of the ores of iron.
Answer:

Question 33.
Define periodicity.
Answer:
The electronic configurations of elements help us to explain the periodic recurrence of physical and chemical properties. Anything which repeats itself after a regular interval is called periodic and this behaviour is called periodicity.

Question 34.
What happens in the combustion zone during the extraction of iron.
Answer:
The temperature in the combustion zone is 150°C. In this region coke bums 02 to form CO₂, when the charge comes in contact with a hot blast of air.

Question 35.
Explain the reactions taking place in the reduction zone.
Answer:
In the upper region of reduction zone, the temperature is at 400°C. In this region CO reduces ferric oxide to form spongy iron.

Question 36.
Define Metallic radius.
Answer:
It is defined as half the distance between the nuclei of adjacent metal atoms.

Question 37.
Complete the following reactions.

1. 4Fe + 10HNO₃ → 4Fe(NO₃)₂ + ………. + 3H₂O
2. 2Fe + 6H₂SO₄ → Fe₂(SO₄)₃ + ………. + 6H₂O

Answer:

1. NH₄NO₃
2. 3SO₂

Question 38.
What happens when steam is passed over red hot iron?
Answer:
When steam is passed over red hot iron magnetic oxide is formed.
3Fe + 4H₂O (steam) → Fe₃O₄ + 4H₂↑

Question 39.
Define Electron affinity.
Answer:
Electron affinity is the amount of energy released when a gaseous atom gains an electron to form its anion. It is also measured in kJ / mol.

Question 40.
Complete the table.
Answer:

Question 41.
Define Metallurgy.
Answer:
Metallurgy is a science of extracting metals from their ores and modifying the metals into alloys for various uses, based on their physical and chemical properties and their structural arrangement of atoms.

Question 42.
Write a short note on leaching or chemical process.
Answer:
This method is employed when the ore is in a very pure form. The ore is treated with a suitable reagent such that the ore is soluble in it but the impurities are not. The impurities are removed by filtration. The solution of the ore, ie., the filtrate is treated with a suitable reagent which precipitates the ore.
E.g. Bauxite Al₂O₃.2H₂O, the ore of aluminium.

Question 43.
Relate all the four columns of the table with their unique properties.
Answer:

Question 44.
Guess Who I am?
(i) I am preserved in Kerosene.
Answer:
Sodium

(ii) My ore is leached with NaOH.
Answer:
Aluminium

(iii) I sacrifice myself to protect my friend Iron.
Answer:
Magnesium

(iv) I am being used in propellers
Answer:
Nickel steel

Question 45.
Explain the method of making alloys.
Answer:

• By fusing the metals together. E.g. Brass is made by melting zinc and copper.
• By compressing finely divided metals. E.g. Wood metal: an alloy of lead, tin, bismuth and cadmium powder is a fusible alloy.

Question 46.
Write the differences between a mineral and a ore.
Answer:

VII. Long answer questions:

Question 1.
Write the reactions taking place during Bessemerisation of copper.
Answer:
2 FeS + 3O₂ → 2FeO + 2SO₂↑

2Cu₂S + 3O₂ → 2 Cu₂O + 2 SO₂↑
2Cu₂O + Cu₂S → 6 Cu + SO₂↑

Question 2.
How do electronegativity values help to find out the nature of bonding between atoms?
Answer:

• If the difference in electronegativity between two elements is 1.7, the bond has 50% ionic character and 50 % covalent character.
• If the difference is less than 1.7, the bond is considered to be covalent.
• If the difference is greater than 1.7, the bond is considered to be ionic.

Question 3.
Explain Froth floatation with diagram.
Answer:
Principle: This process depends on the preferential wettability of the ore with oil (pine oil) and the gangue particles by water. Lighter ores, such as sulphide ores, are concentrated by this method. Eg: Zinc blende (ZnS).

Question 4.
Explain the Baeyer’s process of conversion of Bauxite into alumina.
Answer:
(i) Bauxite ore is finely ground and heated under pressure with a solution of concentrated caustic soda solution at 150°C to obtain sodium meta aluminate.
(ii) On diluting sodium meta aluminate with water, a precipitate of aluminium hydroxide is formed.
(iii) The precipitate is filtered, washed, dried and ignited at 1000°C to get alumina.

Question 5.
Explain the Hall’s Process of electrolytic reduction of alumina with diagram.
Answer:
Hall’s Process:
Aluminium is produced by the electrolytic reduction of fused alumina (Al₂O₃) in the electrolytic cell.
Cathode : Iron tank linked with graphite
Anode : A bunch of graphite rods suspended in molten electrolyte.
Electrolyte : Pure alumina + molten cryolite + fluorspar (fluorspar lowers the fusion temperature of electrolyte)

Temperature: 900 – 950 °C
Voltage used: 5 – 6 V
Overall reaction: 2 Al₂O₃ → 4 Al + 3O₂↑

Question 6.
Write the reaction involved in the middle region of blast furnace during the extraction of iron.
Answer:
The Middle Region (Fusion Zone): The temperature prevails at 1000°C. In this region, CO₂ is reduced to CO.

Limestone decomposes to calcium oxide and CO₂.

These two reactions are endothermic due to absorption of heat. Calcium oxide combines with silica to form calcium silicate slag.
CaO + SiO₂ → CaSiO₃

Question 7.
What are the three different types of iron? Write their uses.
Answer:
(i) Pig iron (Iron with 2-4.5% of carbon): It is used in making pipes, stoves, radiators, railings, manhole covers and drain pipes.
(ii) Steel (Iron with < 0.25% of carbon): It is used in the construction of buildings, machinery, transmission cables and T. V towers and in making alloys.
(iii) Wrought iron (Iron with 0.25-2% of wraught carbon): It is used in making springs, anchors and electromagnets.

Question 8.
What is corrosion? Write the chemistry behind the formation of rust.
Answer:
(i) The slow and steady destruction of a metal by chemical or electro chemical reaction with the environment.
(ii) When the surface of iron is exposed to moisture and other gases present in the atmosphere, the following chemical reaction takes place.
Fe → Fe²⁺ + 2e^–
O₂ + 2H₂O + 4e^– → 4OH^–
O₂ + 4H⁺ + 4e^– → 2H₂O
The Fe²⁺ ions are oxidised to Fe³⁺ ions.
The Fe³⁺ ions combine OH^– ions to form Fe(OH)₃. This becomes rust which is hydrated ferric oxide with the formula Fe₂O₃.xH₂O. It is a reddish brown substance.

Question 9.
Explain the methods of preventing corrosion.
Answer:
(i) Alloying : The metals can be alloyed to prevent the process of corrosion. Eg: Stainless Steel

(ii) Surface Coating : It involves application of a protective coating over the metal. It is of the following types:
(a) Galvanization: It is the process of coating zinc on iron sheets by using electric current.
(b) Electroplating: It is a method of coating one metal over another metal by passing electric current.
(c) Anodizing: It is an electrochemical process that converts the metal surface into a decorative, durable and corrosion resistant. Aluminium is widely used for anodizing process.
(d) Cathodic Protection: It is the method of controlling corrosion of a metal surface protected is coated with the metal which is easily corrodible. The easily corrodible metal is called sacrificial metal to act as anode ensuring cathodic protection.

Question 10.
Discuss the main featured of Periods in the modern periodic table (or) long form of periodic table.
Answer:
The horizontal rows are called periods.There are seven periods in the periodic table.

1. First period (Atomic number 1 and 2): This is the shortest period. It contains only two elements (Hydrogen and Helium).
2. Second period (Atomic number 3 to 10): This is a short period. It contains eight elements (Lithium to Neon).
3. Third period (Atomic number 11 to 18): This is also a short period. It contains eight elements (Sodium to Argon).
4. Fourth period (Atomic number 19 to 36): This is a long period. It contains eighteen elements (Potassium to Krypton). This includes 8 normal elements and 10 transition elements.
5. Fifth period (Atomic number 37 to 54): This is also a long period. It contains 18 elements (Rubidium to Xenon). This includes 8 normal elements and 10 transition elements.
6. Sixth period (Atomic number 55 to 86): This is the longest period. It contains 32 elements (Caesium to Radon). This includes 8 normal elements, 10 transition elements and 14 inner transition elements (Lanthanides).
7. Seventh period (Atomic number 87 to 118): Like the sixth period, this period also accommodates 32 elements. Recently 4 elements have been included by IUPAC.

Question 11.
Discuss the main feature of Groups in the long form of periodic table.
Answer:
(i) The vertical columns in the periodic table starting from top to bottom are called groups. There are 18 groups in the periodic table.

(ii) Based on the common characteristics of elements in each group, they can be grouped as various families.

(iii) The Lanthanides and Actinides, which form part of Group 3 are called inner transition elements.

(iv) Except ‘group O’, all the elements present in each group have the same number of electrons in their valence shell and thus have the same valency. Eg: all the elements of group 1 have one electron in their valence shells (Is¹). So, the valency of all the alkali metals is ‘ 1’.

(v) As the elements present in a group have identical valence shell electronic configurations, they possess similar chemical properties.

(vi) The physical properties of the elements in a group such as melting point, boiling point and density vary gradually.

(vii) The atoms of the ‘group 0’ elements have stable electronic configuration in their valence shells and hence they are unreactive.

VIII. Hot Questions:

Question 1.
Why noble gases have zero electron affinity value?
Answer:
Noble gases show no tendency to accept electrons because the outers and p orbitals of noble gases are completely filled. No more electrons can be added to them and hence their electron affinities are zero.

Question 2.
Arrange the following ions in order of their increasing ionic radii.
Answer:
Li⁺, Mg²⁺, K⁺ Al³⁺
Al³⁺ < Li⁺ < Mg²⁺ < K⁺

Question 3.
Cationic radius is smaller than its corresponding neutral atom. Why?
Answer:
When a neutral atom lose one or more electrons it forms a cation.
Na → Na⁺ + e^–
The radius of this cation (r_Na+)is decreased than its parent atom (r_Na).
When an atom is charged to cation, the number of nuclear charges becomes greater than the number of orbital electrons. Florence the remaining electrons are more strongly attracted by the nucleus. Hence the cationic radius is smaller than its corresponding neutral atom.

Students can download 10th Science Chapter 6 Nuclear Physics Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 6 Nuclear Physics

Samacheer Kalvi 10th Science Nuclear Physics Text Book Back Questions and Answers

I. Choose the correct answer.

Question 1.
Man-made radioactivity is also known as;
(a) Induced radioactivity
(b) Spontaneous radioactivity
(c) Artificial radioactivity
(d) (a) and (c)
Answer:
(a) Induced radioactivity

Question 2.
Unit of radioactivity is _____.
(a) roentgen
(b) curie
(c) becquerel
(d) all the above.
Answer:
(d) all the above.

Question 3.
Artificial radioactivity was discovered by:
(a) Becquerel
(b) Irene Curie
(c) Roentgen
(d) Neils Bohr
Answer:
(b) Irene Curie

Question 4.
In which of the following, no change in mass number of the daughter nuclei takes place _____.
(i) α decay
(ii) β decay
(iii) γ decay
(iv) neutron decay
(a) (i) is correct
(b) (ii) and (iii) are correct
(c) (i) & (iv) are correct
(d) (ii) & (iv) are correct.
Answer:
(b) (ii) and (iii) are correct

Question 5.
……. isotope is used for the treatment of cancer.
(a) Radio Iodine
(b) Radio Cobalt
(c) Radio Carbon
(d) Radio Nickel
Answer:
(b) Radio Cobalt

Question 6.
Gaming radiations are dangerous because of _____.
(a) it affects eyes & bones
(b) it affects tissues
(c) it produces genetic disorder
(d) it produces an enormous amount of heat.
Answer:
(c) it produces genetic disorder

Question 7.
……… aprons are used to protect us from gamma radiations.
(a) Lead oxide
(b) Iron
(c) Lead
(d) Aluminium
Answer:
(c) Lead

Question 8.
Which of the following statements is/are correct?
(i) a particles are photons.
(ii) Penetrating power of γ radiation is very low.
(iii) Ionization power is maximum for a rays.
(iv) Penetrating power of γ radiation is very high.
(a) (i) & (ii) are correct
(b) (ii) & (iii) are correct
(c) (iv) only correct
(d) (iii) & (iv) are correct
Answer:
(d) (iii) & (iv) are correct

Question 9.
Proton-Proton chain reaction is an example of _____.
(a) Nuclear fission
(b) α – decay
(c) Nuclear fusion
(d) β – decay.
Answer:
(c) Nuclear fusion

Question 10.
In the nuclear reaction the value of A and Z.
(a) 8, 6
(b) 8, 4
(c) 4, 8
(d) cannot be determined with the given data
Answer:
(b) 8, 4

Question 11.
Kamini reactor is located at:
(a) Kalpakkam
(b) Koodankulam
(c) Mumbai
(d) Rajasthan
Answer:
(a) Kalpakkam

Question 12.
Which of the following is/are correct?
(i) Chain reaction takes place in a nuclear reactor and an atomic bomb.
(ii) The chain reaction in a nuclear reactor is controlled
(iii) The chain reaction in a nuclear reactor is not controlled
(iv) No chain reaction takes place in an atom bomb
(a) (i) only correct
(b) (i) & (ii) are correct
(c) (iv) only correct
(d) (iii) & (iv) are correct.
Answer:
(b) (i) & (ii) are correct

II. Fill in the blanks.

1. One roentgen is equal to ………… disintegrations per second.
2. Positron is an …………
3. Aneamia can be cured by ………… isotope.
4. Abbreviation of ICRP …………..
5. ………… is used to measure exposure rate of radiation in humans.
6. ………. has the greatest penetration power.
7. _ZY^A → _Z+1Y^A + X; Then, X is …………..
8. _ZX^A → _ZY^A This reaction is possible in …………. decay.
9. The average energy released in each fusion reaction is about …………. J.
10. Nuclear fusion is possible only at an extremely high temperature of the order of ……….. K.
11. The radio isotope of …………. helps to increase the productivity of crops.
12. If the radiation exposure is 100 R, it may cause ………….
Answer:
1. 1.6 × 10¹⁵ disintegrations / second
2. antiparticle [₁e⁰]
3. Radio iron Fe⁵⁹
4. International Commission on Radiological Protection
5. Dosimeter
6. Gama rays
7. X is _-1e⁰
8. gamma
9. 3.84 × 10¹² J
10. 10⁷ to 10⁹ K
11. Radio phosphorus P – 32
12. fatal diseases like leukemia.

III. State whether the following statements are true or false: If false, correct the statement.

1. Plutonium -239 is a fissionable material.
2. Elements having atomic number greater than 83 can undergo nuclear fusion.
3. Nuclear fusion is more dangerous than nuclear fission.
4. Natural uranium U-238 is the core fuel used in a nuclear reactor.
5. If a moderator is not present, then a nuclear reactor will behave as an atom bomb.
6. During one nuclear fission on an average, 2 to 3 neutrons are produced.
7. Einstein’s theory of mass energy equivalence is used in nuclear fission and fusion.
Answer:
1. True
2. False – Elements having atomic number greater than 83 can undergo nuclear fission.
3. True
4. False – Natural U – 238 not used as fuel in a nuclear reactor.
5. True
6. True
7. True

IV. Match the following.

Question 1.
Match the column I with column II.

Answer:
(a) – (iii)
(b) – (i)
(c) – (iv)
(d) – (ii)

Question 2.
Match the column I with column II.

Answer:
(a) – (iv)
(b) – (ii)
(c) – (iii)
(d) – (i)

Question 3.
Match the column I with column II.

Answer:
(a) – (ii)
(b) – (iv)
(c) – (i)
(d) – (iii)

Question 4.
Match the column I with column II.

Answer:
(a) – (iv)
(b) – (iii)
(c) – (ii)
(d) – (i)

Question 5.
Match the column I with column II.

Answer:
(a) – (iii)
(b) – (iv)
(c) – (ii)
(d) – (i)

V. Arrange the following in the correct sequence.

Question 1.
Arrange in descending order, on the basis of their penetration power. Alpha rays, beta rays, gamma rays, cosmic rays
Answer:
gamma rays < beta rays < alpha rays < cosmic rays.

Question 2.
Arrange the following in the chronological order of discovery.
Nuclear reactor, radioactivity, artificial radioactivity, discovery of radium.
Answer:
Discovery of radium, Radioactivity, Artifical radioactivity, Nuclear reactor.

VI. Use the analogy to fill in the blank.

1. Spontaneous process : Natural Radioactivity, Induced process : ………..
2. Nuclear Fusion : Extreme temperature, Nuclear Fission : ………..
3. Increasing crops : Radio phosphorous, Effective functioning of heart : …………
4. Deflected by electric field : a ray, No Deflection : ………….

Answer:

1. artifical radioactivity
2. higher temperature
3. Radio sodium
4. γ-ray

VII. Numerical problems.

Question 1.
₈₈Ra²²⁶ experiences three a – decay. Find the number of neutrons in the daughter element.
Answer:
Mass number of ₈₈Ra²²⁶ is 266
Atomic number of ₈₈Ra²²⁶ is 88
Mass number of α = 4
Atomic number of α = 2
After 3 a decay
Mass number of the daughter element is
= 266 – (3 × 4)
= 266 – 12
= 254
Atomic number of the daughter element is
= 88 – (3 × 2)
= 88 – 6
= 82
Number of neutrons is
= 254 – 82
= 172

Question 2.
A cobalt specimen emits induced radiation of 75.6 millicurie per second. Convert this disintegration in to becquerel (one curie = 3.7 × 10¹⁰ Bq).
Answer:
1 curie = 3.7 × 10¹⁰ Bq
∴ 75.6 × 10^-3 curie = 75.6 × 10^-3 × 3.7 × 10¹⁰
= 279.72 × 10⁷ Bq
= 279.72 × 10⁷ Becquerel

VIII. Assertion and reason type questions.

Question 1.
Assertion: A neutron impinging on U²³⁵, splits it to produce Barium and Krypton.
Reason: U – 235 is a fissile material.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

Question 2.
Assertion: In a 3 – decay, the neutron number decreases by one.
Reason: In 3 – decay atomic number increases by one.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

Question 3.
Assertion: Extreme temperature is necessary to execute nuclear fusion.
Reason: In a nuclear fusion, the nuclei of the reactants combine releasing high energy.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.

Question 4.
Assertion: Control rods are known as ‘neutron seeking rods’.
Reason: Control rods are used to perform sustained nuclear fission reaction.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

IX. Answer in one or two words (VSA).

Question 1.
Who discovered natural radioactivity?
Answer:
Henri Becquerel

Question 2.
Which radioactive material is present in the ore of pitchblende?
Answer:
Uranium is the radioactive material is present in the ore of pitchblende.

Question 3.
Write any two elements which are used for inducing radioactivity?
Answer:
Boron and aluminium

Question 4.
Write the name of the electromagnetic radiation which is emitted during natural radioactivity.
Answer:
Gamma rays are the electromagnetic radiation which is emitted during natural radioactivity.

Question 5.
If A is a radioactive element which emits an α – particle and produces ₁₀₄Rf²⁵⁹. Write the atomic number and mass number of the element A.
Answer:

Mass number A = 259 + 4 = 263
Atomic number Z = 104 + 2 = 106

Question 6.
What is the average energy released from a single fission process?
Answer:
200 MeV

Question 7.
Which hazardous radiation is the cause for the genetic disease?
Answer:
γ – ray (Gamma-ray) or any high energy nuclear particle passes through a human being, it disrupts the entire normal functioning of the biological system and the effect may be an either pathological or genetic disease.

Question 8.
What is the amount of radiation that may cause death of a person when exposed to it?
Answer:
600 R.

Question 9.
When and where was the first nuclear reactor built?
Answer:
The first nuclear reactor was built in 1942 at Chicago, USA.

Question 10.
Give the SI unit of radioactivity.
Answer:
The SI unit of radioactivity is becquerel.

Question 11.
Which material protects us from radiation?
Answer:
Lead

X. Answer the following questions in a few sentences.

Question 1.
Write any three features of natural and artificial radioactivity.
Answer:

Question 2.
Define critical mass.
Answer:
The minimum mass of fissile material necessary to sustain the chain reaction is called ‘critical mass (m_c)’. It depends on the nature, density and the size of the fissile material.

Question 3.
Define one roentgen.
Answer:
One roentgen is defined as the quantity of radioactive substance which produces a charge of 2.58 × 10^-4 coulomb in 1 kg of air under standard conditions of pressure, temperature and humidity.

Question 4.
State Soddy and Fajan’s displacement law.
Answer:
(i) When a radioactive element emits an alpha particle, a daughter nucleus is formed whose mass number is less by 4 units and the atomic number is less by 2 units, than the mass number and atomic number of the parent nucleus.

(ii) When a radioactive element emits a beta particle, a daughter nucleus is formed whose mass number is the same and the atomic number is more by 1 unit, than the atomic number of the parent nucleus.

Question 5.
Give the function of control rods in a nuclear reactor.
Answer:
Control rods are used to control the number of neutrons in order to have a sustained chain reaction. Mostly boron or cadmium rods are used as control rods. They absorb the neutrons.

Question 6.
In Japan, some of the newborn children are having congenital diseases. Why?
Answer:
In Japan, there was a leakage of nuclear radiations in some areas. In those areas, if the new born children handled with careless they are exposed to harmful radiations then they have congenital diseases.

Question 7.
Mr. Ramu is working as an X – ray technician in a hospital. But, he does not wear the lead aprons. What suggestion will you give to Mr. Ramu?
Answer:
The intensity of X-rays is very low. So, X-rays do not produce any severe effects. There are certains clothes that can be used while operating X-ray machines. Ramu can use them and so he may not be severely affected by X-rays, he should avoid eating and drinking when he is working with X-rays.

Question 8.
What is stellar energy?
Answer:
Fusion reaction that takes place in the cores of the Sun and other stars results in an enormous amount of energy, which is called stellar energy.

Question 9.
Give any two uses of radio isotopes in the field of agriculture?
Answer:
The radio isotope of phosphorous (P-32) helps to increase the productivity of crops. The radiations from the radio isotopes can be used to kill the insects and parasites and prevent the wastage of agricultural products.

Question 10.
What is stellar energy?
Answer:
Fusion reaction that takes place in the cores of the Sun and other stars results in an enormous amount of energy, which is called as stellar energy.

XI. Answer the following questions in detail.

Question 1.
Explain the process of controlled and uncontrolled chain reactions.
Answer:
(i) Controlled chain reaction: In the controlled chain reaction the number of neutrons released is maintained to be one. This is achieved by absorbing the extra neutrons with a neutron absorber leaving only one neutron to produce further fission. Thus, the reaction is sustained in a controlled manner. The energy released due to a controlled chain reaction can be utilized for constructive purposes. Controlled chain reaction is used in a nuclear reactor to produce energy in a sustained and controlled manner.

(ii) Uncontrolled chain reaction: In the uncontrolled chain reaction the number of neutrons multiplies indefinitely and causes fission in a large amount of the fissile material. This results in the release of a huge amount of energy within a fraction of a second. This kind of chain reaction is used in the atom bomb to produce an explosion.

Question 2.
Compare the properties of alpha, beta and gamma radiations.
Answer:

Question 3.
What is a nuclear reactor? Explain its essential parts with their functions.
Answer:
A Nuclear reactor is a device in which the nuclear fission reaction takes place in a self-sustained and controlled manner to produce electricity.
Components of a nuclear reactors:
The essential components of a nuclear reactor are

1. fuel,
2. moderator,
3. control rod,
4. coolant and
5. protection wall.

1. Fuel : A fissile material is used as the fuel. The commonly used fuel material is uranium.
2. Moderator : A moderator is used to slow down the high energy neutrons to provide slow neutrons. Graphite and heavy water are the commonly used moderators
3. Control rod : Control rods are used to control the number of neutrons in order to have sustained chain reaction. Mostly boron or cadmium rods are used as control rods. They absorb the neutrons.
4. Coolant : A coolant is used to remove the heat produced in die reactor core, to produce steam. This steam is used to run a turbine in order to produce electricity. Water, air and helium are some of the coolants.
5. Protection wall : A thick concrete lead wall is built around the nuclear reactor in order to prevent the harmful radiations from escaping into the environment.

XII. HOT Questions.

Question 1.
The mass number of a radioactive element is 232 and its atomic number is 90. When this element undergoes certain nuclear reactions, it transforms into an isotope of lead with a mass number 208 and an atomic number 82. Determine the number of alpha and beta decay that can occur.
Answer:
\(_{90} \mathrm{x}^{232} \stackrel{4 \beta}{\longrightarrow} 94^{\mathrm{Y}^{232}+4_{-4} \mathrm{e}^{\circ}}\) (4β decay)
From the result of β decay,
\(94^{232} \stackrel{6 \alpha}{\longrightarrow} 82^{\mathrm{Pb}^{208}+6}_{} \mathrm{He}^{4}\) (6α decay)
The number of α decay = 6
The number of β decay = 4.

Question 2.
‘X – rays should not be taken often’. Give the reason.
Answer:
X-rays have some low intensity. Even then if a person undergoes the exposure of X-ray, his skin may be affected. The tissues near by the bones may be damaged.

Question 3.
Cell phone towers should be placed far away from the residential area – why?
Answer:
From the cell phone towers micro-waves are scattered for a particular area. This may affect small children and aged people. If people are exposed with those rays very often then they may be severly affected.

Samacheer Kalvi 10th Science Nuclear Physics Additional Important Questions and Answers

I. Choose the correct answer.

Question 1.
The elements that undergo spontaneous radioactivity:
(a) Uranium
(b) Radium
(c) Uranium and Radium
(d) None of the above
Answer:
(c) Uranium and Radium

Question 2.
The artificial (or) induced radioactive element is _____.
(a) Uranium
(b) Boron
(c) Radium
(d) none of these.
Answer:
(b) boron

Question 3.
The nucleons in a nucleus are attracted by:
(a) electrostatic force
(b) gravitational force
(c) nuclear force
(d) magnetic force
Answer:
(c) nuclear force

Question 4.
In p decay by one.
(a) mass number decreases
(b) atomic number decreases
(c) neutron number decreases
(d) proton number decreases
Answer:
(c) neutron number decreases

Question 5.
The charge of the α rays _____.
(a) 2e
(b) -e
(c) 0
(d) none of these.
Answer:
(a) 2e

Question 6.
In which process positron is emitted?
(a) natural radioactivity
(b) artifical radioactivity
(c) nuclear fission
(d) nuclear fussion
Answer:
(b) artifical radioactivity

Question 7.
The atomic number of the elements that exhibit natural radioactivity is:
(a) less than 83
(b) more than 83
(c) more than 42
(d) more than 82
Answer:
(b) more than 83

Question 8.
The ionising power of the α rays _____.
(a) 100 times greater than the β rays
(b) 1000 times greater than the γ rays
(c) very less ionization
(d) both (a) and (b).
Answer:
(d) both (a) and (b).

Question 9.
In the reaction  is:
(a) ₆C¹³
(b) ₆C¹²
(c) ₇N¹³
(d) ₈O¹⁶
Answer:
(b) ₆C¹²

Question 10.
Ionising power of β rays _____.
(а) 100 times greater than α rays
(b) 100 times less than α rays
(c) comparatively very less ionization power
(d) 1000 times less than γ rays.
Answer:
(b) 100 times less than α rays

Question 11.
During α – decay the mass number of the daughter element is:
(a) more by 2 units
(b) less by 2 units
(c) more by 4 units
(d) less by 4 units
Answer:
(d) less by 4 units

Question 12.
When α – particle is emitted the atomic number of daughter element is:
(a) more by 4 units
(b) less by 4 units
(c) less by 2 units
(d) more by 2 units
Answer:
(c) less by 2 units

Question 13.
Which power has more penetrating power?
(a) α rays
(b) γ rays
(c) β rays
(d) X rays.
Answer:
(b) γ rays

Question 14.
What is the charge of alpha particle?
(a) -e
(b) +e
(c) zero
(d) +2e^–
Answer:
(d) +2e^–

Question 15.
Which of the following has speed from 1/10 to 1/20 times the speed of light?
(a) β
(b) α
(c) γ
(d) all the above
Answer:
(b) α

Question 16.
In α – decay _____.
(a) atomic number decreases by 2 and the mass number decreases by 4
(b) atomic number increases by 2 and the mass number decrease by 4
(c) there is no change in atomic and mass number
(d) neutron number decreases by one.
Answer:
(a) atomic number decreases by 2 and the mass number decreases by 4

Question 17.
Which of the following is a fertile material?
(a) Thorium – 232
(b) Uranium – 238
(c) Plutonium – 240
(d) All the above
Answer:
(d) All the above

Question 18.
If the mass of the fissile material is less than the critical mass, then it is termed as:
(a) supercritical
(b) critical
(c) subcritical
(d) none of the above
Answer:
(b) critical

Question 19.
1 curie is equal to _____.
(a) the radioactivity of 1 gram of uranium
(b) 1 decay/second
(c) 3.7 × 10¹⁰ becquerel
(d) 1.6 × 10¹² decay / second.
Answer:
(c) 3.7 × 10¹⁰ becquerel

Question 20.
During nuclear fusion which of the following are emitted:
(a) alpha rays
(b) positrons
(c) neutrons
(d) all the above
Answer:
(d) all the above

Question 21.
Anaemia can be diagonised by:
(a) ₁₅P³²
(b) ₂₆Fe⁵⁹
(c) ₁₁Na²⁴
(d) ₂₈Fe⁵⁹
Answer:
(b) ₂₆Fe⁵⁹

Question 22.
I – 131 is used in the treatment of _____.
(a) cancer
(b) skin disease
(c) disease in the thyroid gland
(d) tumour.
Answer:
(c) disease in the thyroid gland

Question 23.
In which decay atomic number of daughter element is increased by 1 unit?
(a) α – decay
(b) β – decay
(c) γ – decay
(d) neutron decay
Answer:
(b) β – decay

Question 24.
in nuclear fusion ………… is satisfied.
(a) law of conservation of energy
(b) law of conservation of momentum
(c) law of conservation angular momentum
(d) mass energy relation
Answer:
(d) mass energy relation

Question 25.
The safe limit of receiving the radiation is about _____.
(a) 100 R
(b) 600 R
(c) 250 R
(d) 250 mR per week.
Answer:
(d) 250 mR per week.

Question 26.
Hydrogen bomb is based on the principle of:
(a) natural radioactivity
(b) induced radioactivity
(c) nuclear fusion
(d) nuclear fission
Answer:
(c) nuclear fusion

Question 27.
Uncontrolled chain reaction yields _____.
(a) nuclear reactor
(b) atom bomb
(c) hydrogen bomb
(d) breeder reactor.
Answer:
(b) atom bomb

Question 28.
In the following reaction.
₁H³ + ₁H² → X + Y + energy X and Y are:
(a) ₂He³, ₀n¹
(b) ₂He⁴, ₀n¹
(c) ₁H², ₀n¹
(d) ₁H³, ₀n¹
Answer:
(b) ₂He⁴, ₀n¹

Question 29.
The number of α and ß particles emitted when ₉₂U²³⁸ decays to ₈₂Pb²⁰⁶ are respectively:
(a) 6, 8
(b) 8, 6
(c) 4, 3
(d) 3, 4
Answer:
(b) 8, 6

Question 30.
The fusion process can be carried out only at a temperature of _____.
(a) 1000°C
(b) 100°C
(c) 104°C
(d) 107 K.
Answer:
(d) 107 K.

Question 31.
Which of the following is used to cure goiter?
(a) Na²⁴
(b) I¹³¹
(c) P³²
(d) Fe⁵⁹
Answer:
(b) I¹³¹

Question 32.
Which radio isotope is used to check the function of heart?
(a) Na²⁴
(b) Fe⁵⁹
(c) Co⁶⁰
(d) I¹³¹
Answer:
(a) Na²⁴

Question 33.
The fuel of the prototype fast breeder reactor is _____.
(a) low enriched uranium
(b) carbides of uranium
(c) high enriched uranium
(d) oxides of plutonium and uranium.
Answer:
(d) oxides of plutonium and uranium.

Question 34.
Which radio isotope is used as a smoke detector?
(a) Cf²³²
(b) I¹³¹
(c) Co⁶⁰
(d) Am²⁴¹
Answer:
(d) Am²⁴¹

Question 35.
The control rod used in a nuclear reactor is _____.
(a) barium
(b) carbon
(c) cadmium
(d) Na.
Answer:
(c) cadmium

II. Fill in the blanks.

1. Radium was discovered by ………..
2. The photoelectric effect is an instantaneous process Natural radioactivity is a ………..
3. The elements with atomic number ……… undergo spontaneous radioactivity.
4. In natural radioactivity emission of radiation is due to ………. of a nucleus.
5. One disintegration per second is equal to ………..
6. S.I unit of radioactivity is ………….
7. The speed of ………. can go upto 9/10 times the velocity of light.
8. α ray is …………
9. ……….ray consists of photons.
10. ………… and ………… are deflected by electric and magnetic fields.
11. When uranium decays into thorium ……….. particle is emitted.
12. In ………… decay there is no change in the mass number of the product nuclear.
13. The minimum mass of a fissile material necessary to sustain the chain reaction is called …………
14. The value of 1MeV in joules is ………..
15. In the transformation ₁H² + ₁H² → X + energy. X is …………
16. Einstein’s mass energy relation is ………….
17. ……….causes the mutation in the human gene.
18. ……….. is also used in treatment of skin cancer.
19. The safe limit for receiving the radiation is ………….
20. The substances that are used as coolants are ………….. and
21. ………… reactors convert non-fissionable material units.
22. The expansion of BARC is ………….
23. The number of nuclear reactor that are operating in India are ……………
24. Identify X in the following transformation ₁₂Mg²⁴ + ₀n¹ → X + ₁n¹. X is ………….
25. In the reaction ₉₂U²³⁸ + ₀n¹ → ₉₃NP²³⁹ + X. X is ………….
Answer:
1. Marie Curie and pierre Curie
2. Spontaneous
3. more than 83
4. self-disintegration
5. Becquerel
6. Becquerel
7. β rays
8. a helium nucleus
9. Gamma
10. Alpha, beta
11. alpha
12. beta
13. critical mass
14. 1.602 × 10^-13 J
15. ₂He⁴
16. E = mc²
17. Gamma radiation
18. Radio-gold Au¹⁹⁸
19. 100 mR per week
20. Water, air and helium
21. Breeder
22. Bhaba Atomic Research Centre
23. 22
24. ₁₁Na²⁴
25. _-1e⁰

III. State whether the following statements are true or false: If false, correct the statement.

1. Artificial radioactivity is induced in the elements like boron, aluminum etc.
2. Natural radioactivity can be controlled.
3. 1 Rd = 3.7 × 10¹⁰ disintegrations / second.
4. The S.I units of radioactivity is roentgen.
5. The charge of each beta particle is – e
6. Beta ray travels with velocity of light.
7. Example for alpha decay is ₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴
8. Otto Hann and Strassman discovered nuclear fission.
9. In the mass of the fissile material is more than the critical mass it is termed as supercritical.
10. Hydrogen bomb is based on uncontrolled chain reaction.
11. 1eV = 1.602 × 10^-16 Joule.
12. Hydrogen is based on nuclear fusion.
13. Positrons are emitted in nuclear fusion.
14. To diagnose anaemia P³² is used.
15. Radio phosphorous is used in the treatment of skin diseases.
16. To prevent the leakage of nuclear radiation concrete wall with lead lining is used.
Answer:
1. True
2. False – Artificial radio activity can be controlled.
3. False – 1 curie = 3.7 × 10¹⁰⁶ disintegrations / second.
4. False – The S.l unit of radioactivity is Becquerel.
5. True
6. False – Gamma ray travels with velocity of light.
7. True
8. True
9. True
10. False – Atom bomb is based on uncontrolled chain reaction.
11. False – 1eV = 1.602 × 10^-9 Joule
12. True
13. True
14. False – To diagonise aneamia Fe⁵⁹ is used.
15. True
16. True
17. True

IV. Match the following.

Question 1.
Match the Column I with Column II.

Answer:
(a) – (iii)
(b) – (iv)
(c) – (v)
(d) – (i)

Question 2.
Match the Column I with Column II.

Answer:
(a) – (iv)
(b) – (v)
(c) – (ii)
(d) – (i)

Question 3.
Match the Column I with Column II.

Answer:
(a) – (v)
(b) – (iv)
(c) – (i)
(d) – (ii)

V. Numerical problems.

Question 1.
A radioactive isotope emits radiation of 7.4 × 10⁴ G Bq per second. Convert this disintegration in terms of curie.
Answer:
One curie = 3.7 × 10¹⁰ Becquerel
Becquerel (1 Bq) = One disintegration / second
∴ 1 Bq = \(\frac{1}{3.7×10^{10}}\) curie
∴ 7.4 × 10⁴ G Bq
= 7.4 × 10⁴ × 10⁹ × \(\frac{1}{3.7×10^{10}}\)
= 2 × 10³ curie
= 2,000 curie

Question 2.
The isotope ₉₂U²³⁸ successfully undergoes three α – decays and two β – decays. What is the resulting isotope?
Answer:
Number and nature of decays = 3α and 2β
Atomic number of isotope is Z = 92
Mass number of isotope is A = 238
Resulting isotope:
After the emission of 3α particles atomic number
Z’ = Z = (3 × 2)
= Z – 6
= 92 – 6
Z’ = 86
After the emission of 2β particles atomic number
Z” = Z – 2 (-1) = 86 + 2 = 88
Mass number after the emission of 3α particles
A’ = A – 3α
= 238 – 3(4)
= 238 – 12
= 226
Mass number after the emission of 2β particles
A” = A’ – 2(0)
= 226
∴ Resulting isotope is ₈₈Ra²²⁶

Question 3.
₈₈Ra²²⁶ experiences one α – decay and one β – decay. Calculate the number of neutrons in the final daughter nucleus that is formed.
Answer:
α particle = ₂He⁴
Atomic number of α particle = 2
Mass number of α particle = 4

Number of neutrons = Mass number – atomic number
= 222 – 87 = 135

Question 4.
State the number of protons, electrons neutrons and nucleons in ₄Be⁹ atom.
Answer:
Atomic number of ₄Be⁹ atom Z = 4
Mass number of ₄Be⁹ atom A = 9
Number of protons = Atomic number Z = 4
Number of neutrons = A – Z = 9 – 4 = 5
Number of nucleons = A = 9

Question 5.
Determine X and Y in the following transformations.
(i) ₄Be⁹ + α → X
(ii) ₉₂U²³⁵ + ₀n¹ → ₅₀Ba¹⁴¹ + Y + 3₀n¹
Answer:
(i) ₄Be⁹ + ₂He⁴ → ₆C¹³ [α = ₂He⁴]
∴ X = ₆C¹³

(ii) ₉₂U²³⁵ + ₀n¹ → ₅₀Ba¹⁴¹ + Y + 3₀n¹
Equating atomic number on both sides we get,
235 + 1 = 141 + A + 3
236 = 144 + A
∴ A = 236 – 144
= 92
Equating atomic number on both sides are get
92 + 0 = 56 + 2 + 0
Z = 92 – 56 = 36
∴ Y is ₃₆Kr⁹²

Question 6.
Calculate the amount energy released when a radioactive element undergoes fusion and results in a mass defect of 4g.
Answer:
Velocity of light = 3 × 10⁸ m/s
Mass defect Δm = 4 × 10^-3
By Einstein’s equation, energy released
E = mC²
= (4 × 10^-3) × (3 × 10⁸)²
= 36 × 10¹³ J
= 3.6 × 10¹⁴ J

Question 7.
Identify the radio isotopes in the following reactions.
Answer:
(i) ₁₅P⁸ + ₀n¹ → X + γ
(ii) ₀n¹ → _ZY^A + _-1e⁰ + γ^–
Answer:
(i) ₁₅P³¹ + ₀n¹ → X + γ
Mass number of X = 31 + 1 = 32
Atomic number of Y= 15 + 0 =15
∴ X is ₁₅P³¹

(ii) ₀n¹ → _ZY^A + _-1e⁰ + γ^–
Mass number 1 = A + 0
∴ A = 1
Atomic number 0 = Z – 1
∴ Z = 1
_ZY^A is ₁H¹

VI. Assertion and reason type questions.

Question 1.
Assertion: Natural radioactivity is a spontaneous process.
Reason: It cannot be controlled.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

Question 2.
Assertion: In artificial radioactivity neutron and positron are emitted. Reason: It can be controlled.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.

Question 3.
Assertion: p rays are electrons.
Reason: p rays travel with speed of light.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(c) If the assertion is true, but the reason is false.

Question 4.
Assertion: Gamma rays have maximum ionising power.
Reason: Alpha rays have low penetrating power.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(d) If the assertion is false, but the reason is true.

Question 5.
Assertion: Critical mass of a fissile material is the mass necessary to sustain chain reaction.
Reason: Critical mass depends on the nature, density and size of the fissile material.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(c) If the assertion is true, but the reason is false.

Question 6.
Assertion: Nuclear fusion takes place in the cores of the sun and other stars.
Reason: Nuclear fusion is called as thermonuclear reaction.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

Question 7.
Assertion: An alpha particle carries double the positive charge of protons.
Reason: The charge of alpha particle is equal to charge on the helium nucleus.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

Question 8.
Assertion: Gamma rays are electromagnetic waves.
Reason: Gamma rays travel with speed of light.
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

VII. Answer in one or two words (VSA).

Question 1.
Who discovered the nucleus?
Answer:
Rutherford

Question 2.
Define ‘Natural Radioactivity’.
Answer:
This phenomenon of spontaneous emission of radiation from certain elements on their own is called ‘Natural radioactivity’.

Question 3.
State elements exhibiting radioactivity with atomic number less than 83.
Answer:
Uranium and radium

Question 4.
What is the nature of radioactive substances?
Answer:
They are earth metals and transition metals.

Question 5.
Define ‘One Rutherford (Rd)’.
Answer:
It is another unit of radioactivity. It is defined as the quantity of a radioactive substance, which produces 106 disintegrations in one second.
1 Rd = 10⁶ disintegrations per second.

Question 6.
In ₄Be⁹ + ₂He⁴ → X. What is X?
Answer:
X is ₆C¹³

Question 7.
What is the value of 1 curie?
Answer:
1 curie = 3.7 × 10¹⁰ disintegrations / second.

Question 8.
State the value of Rutherford.
Answer:
1 Rutherford = 10⁶ disintegrations / second.

Question 9.
Explain the term ‘fissile material’ Give an example.
Answer:
Fissionable material is a radioactive element, which undergoes fission in a sustained manner when it absorbs a neutron. It is also termed as ‘fissile material’.
E.g. U²³⁵, plutonium (Pu²³⁹ and Pu²⁴¹)

Question 10.
Which ray has greatest ionising power?
Answer:
Alpha ray

Question 11.
Which ray posses minimum ionising power?
Answer:
Gamma ray

Question 12.
Which ray is not deflected by electric and magnetic fields?
Answer:
Gamma ray

Question 13.
Name the ray that travels with speed about 9/10 times that of light?
Answer:
Beta ray

Question 14.
What is the charge of particle?
Answer:
It’s charge is +2e.

Question 15.
Which particle has a charge of -e?
Answer:
Beta particle

Question 16.
State that the ray consisting of protons.
Answer:
Gamma ray

Question 17.
When uranium emits an alpha particle which element is obtained as daughter element.
Answer:
Thorium ₉₀Th²³⁴

Question 18.
Mention the value of 1eV in terms of joule.
Answer:
1eV = 1.602 × 10^-19 joule

Question 19.
What is the value of 1Mev?
Answer:
1MeV = 10⁶eV = 1.602 × 10^-13 joule

Question 20.
Which radio isotope is used in the treatment of skin diseases?
Answer:
Radio Phosphorus P³²

Question 21.
What is the use of radio iodine?
Answer:
Radio iodine is used to cure goiter.

Question 22.
Which isotope is used in airlines?
Answer:
Califorium Cf²³² is used in airlines.

Question 23.
State the isotope used as a smoke detector.
Answer:
Americium Am²⁴¹

Question 24.
Write down the uses of a nuclear reactor.
Answer:
Uses of a nuclear reactor

• Nuclear reactors are widely used in power generation.
• They are also used to produce radioisotopes, which are used in a variety of applications
• Some reactors help us to do research in the field of nuclear physics.
• Breeder reactors are used to convert non-fissionable materials into fissionable materials.

Question 25.
What are gamma rays?
Answer:
Gamma rays are electromagnetic waves consisting of photons.

Question 26.
Who discovered Cathode rays.
Answer:
J.J. Thomson

VIII. Answer the following question in few sentences.

Question 1.
What is radioactivity?
Answer:
The phenomenon of nuclear decay of certain elements with the emission of radiations like alpha, beta, and gamma rays is called ‘radioactivity’.

Question 2.
What is meant by natural radioactivity?
Answer:
This phenomenon of spontaneous emission of radiation from certain elements on their own is called ‘natural radioactivity’.

Question 3.
Define Rutherford.
Answer:
It is defined as the quantity of a radioactive substance, which produces 106 disintegrations in one second.
1 Rd = 10⁶ disintegrations per second.

Question 4.
What is the unit of radioactivity? Define it.
Answer:
The SI unit of radioactivity is becquerel. It is defined as the quantity of one disintegration per second.

Question 5.
Define nuclear fission. State an example.
This process of breaking (splitting) up of a heavier nucleus into two smaller nuclei with the release of a large amount of energy and a few neutrons is called ‘nuclear fission’.
Eg: Nuclear fission of a uranium nucleus (U²³⁵)
₉₂U²³⁵ + ₀n¹ → ₅₆Ba¹⁴¹ + ₃₆Kr⁹² + 3₀n¹ + Q (energy)

Question 6.
How a product nucleus is identified in a nuclear reaction?
Answer:
In a nuclear reaction, the element formed as the product nucleus is identified by the atomic number of the resulting nucleus and not by its mass number.

Question 7.
What is fissile material?
Answer:
A fissionable material is a radioactive element, which undergoes fission in a sustained manner when it absorbs a neutron. It is also termed as ‘fissile material’.
Eg: U²³⁵, plutonium (Pu²³⁹ and Pu²⁴¹)

Question 8.
What are fertile materials? Mention examples.
Answer:
There are some radioactive elements, which can be converted into fissionable material. They are called as fertile materials.
Eg: Uranium – 238, Thorium – 232, Plutonium – 240.

Question 9.
What is the composition of natural uranium?
Answer:
Natural uranium consists of 99.28 % of ₉₂U²³⁸ and 0.72 % of ₉₂U²³⁵.

Question 10.
What is nuclear fusion? State an example.
Answer:
The process in which two lighter nuclei combine to form a heavier nucleus is termed as ‘nuclear fusion’.
Eg: ₁H² + ₁H² → ₂He⁴ + Q (Energy)

Question 11.
What is meant by chain reaction?
Answer:
A chain reaction is a self-propagating process in which the number of neutrons goes on multiplying rapidly almost in a geometrical progression.

Question 12.
What is meant by mass defect?
Answer:
The mass of the daughter nucleus formed during a nuclear reaction (fission and fusion) is lesser than the sum of the masses of the two parent nuclei. This difference in mass is called mass defect.

Question 13.
Nuclear fusion is named as thermonuclear reaction. Why?
Answer:
Nuclear fusion is possible only at an extremely high temperature of the order of 10⁷ to 10⁹ K and a high pressure to push the hydrogen nuclei closer to fuse with each other. Hence, it is named as ‘Thermonuclear reaction’.

Question 14.
What are the uses of radio isotopes in industries?
Answer:

1. An isotope of californium (Cf²⁵²) is used in the airlines to detect the explosives in the luggage.
2. An isotope of Americium (Am²⁴¹) is used in many industries as a smoke detector.

Question 15.
What is the age of Earth?
Answer:
It is nearly 4.54 × 10⁹ years (around 45 Crore 40 lakh years).

Question 16.
What do you know about dosimeter?
Answer:
Dosimeter is a device used to detect the levels of exposure of an ionizing radiation.

Question 17.
What is the function of moderator in a nuclear reactor?
Answer:
A moderator is used to slow down the high energy neutrons to provide slow neutrons. Graphite and heavy water are the commonly used moderators.

Question 18.
How do coolants function in a nuclear reactor?
Answer:
A coolant is used to remove the heat produced in the reactor core, to produce steam. This steam is used to run a turbine in order to produce electricity. Water, air and helium are some of the coolants.

Question 19.
Name some operating reactors in India.
Answer:
Cirus, Dhuruva and Pumima.

Question 20.
Define Curie.
Answer:
Curie is defined as the quantity of a radioactive substance, which undergoes 3.7 × 10¹⁰ disintegrations in one second. This is actually close to the activity of 1 g of radium-226.

IX. Answer the following question in detail.

Question 1.
Write short notes on induced radioactivity.
Answer:
The phenomenon by which even light elements are made radioactive, by artificial or induced methods, is called ‘artificial radioactivity’ or ‘man-made radioactivity’.

This kind of radioactivity was discovered by Irene Curie and F.Joliot in 1934. Artificial radioactivity is induced in certain lighter elements like boron, aluminium etc., by bombarding them with radiations such as ‘alpha particles’ emitted during the natural radioactivity of uranium. This also results in the emission of invisible radiations and elementary” particles. During such a disintegration, the nucleus which undergoes disintegration is called ‘parent nucleus’ and that which is produced after the disintegration is called a ‘daughter nucleus’. The panicle, which is used to induce the artificial disintegration is termed as projectile and the particle which is produced after the disintegration is termed as ejected panicle. When the projectile hits the parent nucleus, it is converted into an unstable nucleus, which in turn decays spontaneously emitting the daughter nucleus along with an ejected particle.

If you denote the parent and daughter nuclei as X and Y respectively, then the nuclear disintegration is represented as follows: X (P,E) Y. Here, P and E represent the projectile particle and ejected particle respectively.
₄Be⁹ + ₂He⁴ → ₆C^13*
₆C^13* → ₆C¹² + ₀n¹
In the above nuclear reaction, ₆C^13* is unstable and is radioactive. This reaction can be represented as ₄Be⁹ (α, n) ₄C¹²
₄Be⁹ + ₂He⁴ → ₆C¹² + ₀n¹

Question 2.
Explain the concept of ‘Hydrogen bomb’.
Answer:
Hydrogen Bomb:

• This releases a huge amount of energy in a very small time interval and leads to a Hydrogen bomb is based on the principle of nuclear fusion.
• A hydrogen bomb is always designed to have an inbuilt atom bomb which creates the high temperature and pressure required for fusion when it explodes.
• Fusion takes place in the hydrogen core and leads to the release of a very large amount of energy in an uncontrolled manner.
• The energy released in a hydrogen bomb (or fusion bomb) is much higher than that released in an atom bomb (or fission bomb).

Question 3.
Explain
(i) alpha decay,
(ii) Beta decay,
(iii) gamma decay
Answer:
(i) Alpha decay : A nuclear reaction in which an unstable parent nucleus emits an alpha particle and forms a stable daughter nucleus, is called, ‘alpha decay’.
Eg: Decay of uranium (U²³⁸) to thorium (Th²³⁴) with the emission of an alpha particle.
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ (α – decay)
In α – decay, the parent nucleus emits an a particle and so it is clear that for the daughter nucleus, the mass number decreases by four and the atomic number decreases by two.

(ii) Beta decay : A nuclear reaction, in which an unstable parent nucleus emits a beta particle and forms a stable daughter nucleus, is called ‘beta decay’.
Eg: Beta decay of phosphorous.
₁₅P³² → ₁₆S³² + _-1e⁰(β – decay)
In β – decay there is no change in the mass number of the daughter nucleus but the atomic number increases by one. In a nuclear reaction, the element formed as the product nucleus is identified by the atomic number of the resulting nucleus and not by its mass number.

(iii) Gamma decay: In a γ – decay, only the energy level of the nucleus changes. The atomic number and mass number of the radioactive nucleus remain the same.

Question 4.
What is the principle of atom bomb? Describe its structure.
Answer:
The atom bomb is based on the principle of uncontrolled chain reaction. In an uncontrolled chain reaction, the number of neutrons and the number of fission reactions multiply almost in a geometrical progression. This releases a huge amount of energy in a very small time interval and leads to an explosion.

Structure : An atom bomb consists of a piece of fissile material whose mass is subcritical. This piece has a cylindrical void. It has a cylindrical fissile material which can fit into this void and its mass is also subcritical. When the bomb has to be exploded, this cylinder is injected into the void using a conventional explosive. Now, the two pieces of fissile material join to form the supercritical mass, which leads to an explosion. The structure of an atom bomb.

During this explosion tremendous amount of energy in the form of heat, light and radiation is released. A region of very high temperature and pressure is formed in a fraction of a second along with the emission of hazardous radiation like y rays, which adversely affect the living creatures. This type of atom bombs were exploded in 1945 at Hiroshima and Nagasaki in Japan during the World War II.

Question 5.
What precautions are to he took for those, who are working in radiation laboratories?
Answer:

1. Radio – Iodine (I¹³¹) is used to cure goitre.
2. Radioactive materials should be kept in a thick-walled lead container.
3. Lead coated aprons and lead gloves should be used while working with hazardous radioactive materials.
4. We should avoid eating while handling radioactive materials.
5. The radioactive materials should be handled only by tongs or by a remote control device.
6. Dosimeters should be worn by the users to check the level of radiation.

Question 6.
What do you know about hydrogen bomb?
Answer:
Hydrogen bomb is based on the principle of nuclear fusion. A hydrogen bomb is always designed to have an inbuilt atom bomb which creates the high temperature and pressure required for fusion when it explodes. Then, fusion takes place in the hydrogen core and leads to the release of a very large amount of energy in an uncontrolled manner. The energy released in a hydrogen bomb (or fusion bomb) is much higher than that released in an atom bomb (or fission bomb).

Question 7.
What are the applications of radio isotopes in medicine?
Answer:
Medical applications of radio isotopes can be divided into two parts:

1. Diagnosis
2. Therapy

Radio isotopes are used as tracers to diagnose the nature of circulatory disorders of blood, defects of bone metabolism, to locate tumors, etc., Some of the radio isotopes which are used as tracers are: hydrogen, carbon, nitrogen, sulphur, etc.

1. Radio-sodium (Na²⁴) is used for the effective functioning of heart.
2. Radio-Iodine (I¹³¹) is used to cure goiter.
3. Radio-iron is (Fe⁵⁹) is used to diagnose anaemia and also to provide treatment for the same.
4. Radio-phosphorous (P³²) is used in the treatment of skin diseases.
5. Radio-cobalt (Co⁶⁰) and
6. Radio-gold (Au¹⁹⁸) are used in the treatment of skin cancer.
7. Radiations are used to sterilize the surgical devices as they can kill the germs and microbes.

Question 8.
Mention the applications of radio isotopes in agriculture and industries and archeological research.
Answer:
Agriculture : The radio isotope of phosphorous (P-32) helps to increase the productivity of crops. The radiations from the radio isotopes can be used to kill the insects and parasites and prevent the wastage of agricultural products. Certain perishable cereals exposed to radiations remain fresh beyond their normal life, enhancing the storage time. Very small doses of radiation prevent sprouting and spoilage of onions, potatoes and gram.

Industries : In industries, radioactive isotopes are used as tracers to detect any manufacturing defects such as cracks and leaks. Packaging faults can also be identified through radio activity. Gauges, which have radioactive sources are used in many industries to check the level of gases, liquids and solids.

1. An isotope of californium (Cf ²⁵²) is used in the airlines to detect the explosives in the luggage.
2. An isotope of Americium (Am²⁴¹) is used in many industries as a smoke detector.

Archeological research : Using the technique of radio carbon dating, the age of the Earth, fossils, old paintings and monuments can be determined. In radio carbon dating, the existing amount of radio carbon is determined and this gives an estimate about the age of these things.

Question 9.
Compare the features of nuclear fission with nuclear fusion.
Answer:

Question 10.
Mention the preventive measures to be followed while working with radioactive materials.
Answer:
Radioactive materials should be kept in a thick walled lead container.

1. Lead coated aprons and lead gloves should be used while working with hazardous radioactive materials.
2. You should avoid eating while handling radioactive materials.
3. The radioactive materials should be handled only by tongs or by a remote control device.
4. Dosimeters should be worn by the users to check the level of radiation.

Question 11.
Write a note on nuclear power plants in India.
Answer:
Indian Atomic Energy Commission (AEC) was established in August 1948 by the Department of Indian Scientific Research committee at Bombay (now Mumbai) in Maharashtra. It is the nodal agency for all the research done in the field of atomic energy. Dr. Homi Jahangir Bhaba was the first chairman of Indian Atomic Energy Commission. Now, it is known as Bhaba Atomic Research Centre (BARC).

Nuclear power is the fifth largest source of power in India. Tarapur Atomic Power Station is India’s first nuclear power station. Now, there are a total of seven power stations, one each in Maharashtra, Rajasthan, Gujarat, Uttar Pradesh and two in Tamilnadu. In Tamilnadu, we have nuclear power stations in Kalpakkam and Kudankulam. Apsara was the first nuclear reactor built in India and Asia. Now, there are 22 nuclear reactors which are operating in India. Some other operating reactors are

1. Cirus
2. Dhuruva
3. Pumima

Question 12.
Distinguish (i) atom bomb from Nuclear reactor,
(ii) Nuclear fission from Nuclear fusion.
Answer:
(i) atom bomb from nuclear reactor:

(ii) Nuclear fission from Nuclear fusion

X. Hot Questions.

Question 1.
A neutron is most effective as bulet in nuclear reactions. Why?
Answer:
This is because a neutron carries no charge. It can hit the nucleus directly without being repelled or attracted by the nucleus or electrons.

Question 2.
Why is \({ _{ 92 } }U^{ 238 }\) not suitable for chain reaction?
Answer:
Only fast-moving neutrons of 12 MeV can cause fission of \({ _{ 92 } }U^{ 238 }\) nuclei. But such neutron has fewer chances of interaction. They escape the fissionable material without causing fission.

Question 3.
Why cadmium is used as control rods in the nuclear reactor?
Answer:
As Cadmium has a high cross section for absorption of neutrons, cadmium is used as control rod.

Question 4.
Why is nuclear fusion not possible in a laboratory (or) Why is nuclear fusion difficult to carry out?
Answer:
Nuclear fusion requires a very high temperature of 10⁶ – 10⁷ K. This temperature is attained by causing an explosion due to the fission process. Moreover, no solid container can withstand such a high temperature.

Question 5.
Why is the penetrating power of a – particle is less than that of β – particle?
Answer:
Ionising power is directly proportional to kinetic energy that varies directly as mass of particle and square of its velocity. Hence ionising power of an alpha particle is more than that of β particle.

Question 6.
Why heavy water is used to slow down the fast moving neutrons?
Answer:
Since heavy water (D₂O) is rich in hydrogen, it is used to slow down the fast moving neutrons.

Question 7.
The penetrating power of α – particle is less than that of β – particle – Why?
Answer:
(i) Penetrating power varies inversely as mass of the particle. But mass of alpha particles is very much greater than mass of beta particles.
(ii) Hence, penetrating power of α – particle is less than that of β – particles.

Question 8.
What are the units of activity of radio active elements?
Answer:
1 curie = 3.7 × 10¹⁰ disintegrations / second
1 rutherford = 10⁶ disintegrations / second