Category: Class 11

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Bio Botany Guide Pdf Chapter 7 Cell Cycle Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Bio Botany Solutions Chapter 7 Cell Cycle

11th Bio Botany Guide Cell Cycle Text Book Back Questions and Answers

Choose The Correct Answer:

Question 1.
The correct sequence in cell cycle is
a) S M G1 G2
b) S G1 G2 M
c) G1 S G2 M
d) M G1 G2 S
Answer:
c) G1 S G2 M

Question 2.
If mitotic division is restricted in G, phase the cell cycle, then the condition is known as
a) S Phase
b) G₂ Phase
c) M Phase
d) G₀ phase
Answer:
d) G₀ phase

Question 3.
Anaphase promoting complex APC is a protein degradation machinery necessary for proper mitosis of animal cells. If APC is defective in a human cells. Which of the following is expected to occur?
a) Chromosomes will be fragmented
b) Chromosomes will not condense
c) Chromosomes will not regregate
d) Recombination of Chromosomes will occur
Answer:
c) Chromosomes will not segregate

Question 4.
In the S phase of cell cycle
a) Amount of DNA doubles in each cell
b) Amount of DNA remain same in each cell
c) Chromosome number is increased
d) Amount of DNA is reduced to half in each cell
Answer:
a) Amount of DNA doubles in each cell

Question 5.
The centromere is required for
a) Transcription
b) Crossing over
c) Cytoplasmic cleavage
d) movement of chromosome towards the pole
Answer:
d) movement of chromosome towards the pole

Question 6.
Synapsis occurs between
a) m RNA and ribosomes
b) spindle fibres and centromeres
c) two homologous chromosomes
d) a male and a female gemale
Answer:
c) two homologous chromosomes

Question 7.
In meiosis crossing over is initiated at
a) Diplotene
b) Pachytene
c) Leptotene
d) Zygotene
Answer:
b) Pachytene

Question 8.
Colchicine prevents the mitosis of the cells at which of the following stage
a) Anaphase
b) Metaphase
c) Prophase
d) Interphase
Answer:
a) Anaphase

Question 9.
The pairing of homologous chromosomes on meiosis is known as
a) Bivalent
b) Synapsis
c) Disjunction
d) Synergids
Answer:
b) Synapsis

Question 10.
Anastral mitosis is the characteristic feature of
a) Lower animals
b) Higher animals
c) Higher plants
d) All living Organism
Answer:
c) Higher plants

Question 11.
Write any three significance of mitosis
Answer:
Exact copy of the parent cell is produced by mitosis (genetically identical).

1. Genetic stability – daughter cells are genetically identical to parent cells.
2. Repair of tissues – damaged cells must be replaced by identical new cells by mitosis.
3. Regeneration – Arms of starfish.

Question 12.
Differentiate between Mitosis and Meiosis.
Answer:
Differences between Mitosis and Meiosis

Mitosis	Meiosis
One division	Two division
The number of chromosomes remains the same	The number of chromosomes is halved
Homologous chromosomes line up separately on the metaphase plate	Homologous chromosomes line up in pairs at the metaphase plate
Homologous chromosome do not pair up	Homologous chromosome pair up to form bivalent
Chiasmata do not form and crossing over never occurs	Chiasmata form and crossing over occurs
Daughter cells are genetically identical	Daughter cells are genetically different from the parent cells
Two daughter cells are formed	Four daughter cells are formed

Question 13.
Differentiate Cytokinesis in plant cells & animal cells
Answer:

Question 14.
Given an account of the Go phase.
Answer:
Some cells exit G₁ and enters a quiescent stage called G₀, where the cells remain metabolically active without proliferation. Cells can exist for long periods in G₀ phase. In G₀ cells cease growth with reduced rate of RNA and protein synthesis. The G₀ phase is not permanent. Mature neuron and skeletal muscle cell remain permanently in G₀. Many cells in animals remains in G₀ unless called onto proliferate by appropriate growth factors or other extracellular signals. G₀ cells are not dormant.

Question 15.
Write about the Pachytene and Diplotene stage of Prophase I.
Answer:

3. Pachytene stage

• Chromosome appear as bivalent or tetrads
• 4 chromatids & 2 centromeres are seen
• Synapsis of homologous chromosomes between non-sister chromatids completes except at chiasmata where crossing over occurs
• Recombination (exchange of chromosomal bits is completed by the end) – but chromosomes are linked at the sites of crossing over
• Enzyme – Recombinase mediates the process.

4. Diplotene

• Synaptonemal complex disassembled & dissolves
• Nonsister chromatids of homologous chromosomes get attached where x like shape occur at Crossing over known as chiasmata holding the homologous chromosomes together the homologous chromosomes tend to separate except at chiasmat
• The sub-stage last for days or years depending on the sex & the organism follows Pachytene
• synaptical complex disassembled & dissolves
• The chromosomes are actively transcribed in females as the eggs stores up materials for embryonic development
• Exception In Lamp brush chromosome prominent loops occur.
  

11th Bio Botany Guide Cell Cycle Additional Important Questions and Answers

I.Choose the correct answer: (1 Marks)

Question 1.
Most of the neurons in the brain are in …………… stage.
(a) G₁
(b) S
(c) G₂
(d) G₀
Answer:
(d) G₀

Question 2.
Un differentiated cells include
a) Stem cells in animals
b) Meristematic cells in plants
c) RBC which carry out the transportation of oxygen
d) Mesophyll cells which carry out photosynthesis
(i) a & b
(ii) c & d
(iii) a & c
(iv) b & c
Answer:
(i) a & b

Question 3.
Robert Brown discovered the nucleus in the cells of …………… roots.
(a) Mirabilis
(b) Orchid
(c) Moringa
(d) Oryza
Answer:
(b) Orchid

Question 4.
The proteins that activate the cell to perform cell division are
a) Actin and Myosin
b) Kinases and Cyclin
c) Histamine and Cyclin
d) Tubulin and Actin
Answer:
b) Kinases & Cyclin

Question 5.
The number of chromosomes in the onion cell is …………….
(a) 8
(b) 16
(c) 32
(d) 64
Answer:
(a) 16

Question 6.
Mitosis is called
a) Direct cell division
b) Indirect cell division
c) Mitotic Meiotic cell division
d) Reduction division
Answer:
a) Direct cell division

Question 7.
During Anaphase
(I) The daughter chromosome move to the opposite poles due to the shortening of the phragmoplast
(II) due to the thickening of chromosomes
(III) Shortening of microtubules
(IV) Shortening of asters
Answer:
(III) Shortening of microtubules

Question 8.
Cell cycle was discovered by …………….
(a) Singer & Nicolson
(b) Prevost & Dumans
(c) Schleider & Schwann
(d) Boveri
Answer:
(b) Prevost & Dumans

Question 9.
The cells without nucleus are
a) RBC – platelets, tracheids & vessels
b) RBC – sievetube, companion cells thrombocytes
c) WBC – platelets, companion cells & vessels
d) RBC – platelets, companion cells & neurons
Answer:
a) RBC – platelets, tracheids & vessels

Question 10.
The stage between two meiotic division is called
a) Cytokinesis
b) Interphase I
c) Inter kinesis
d) Interphase II
Answer:
c) Inter kinesis

Question 11.
Replication of DNA occurs at …………… phase.
(a) G₀
(b) G₁
(c) S
(d) G₂
Answer:
(c) S

II. Find out the true and false statements from the following and on that basis find the correct answer.

Question 1.
(I) Nucleolus disappear during the metaphase stage of mitosis
(II) The microtubules arrange to form asters in plant cells
(III) In plant cells phragmoplast is formed prior to the formation of cell plate
(IV) Mitosis is responsible for the Regeneration of lost arms of starfish

Answer:
b) False – False – True- True

Question 2.
(i) The word Protoplasm was coined by – Purkinje
(ii) Structure of bacteria was observed first – Edouard Van Beneden through a microscope by
(iii) Centrosome & Chromosome theory – Theodor Boveri Proposed by
(iv) Cell division in round Worm was – Walther Flemming Observed by

Answer:
b) True – False – True – False

Question 3.
(i) C Value is the amount in picograms of DNA contained within a haploid Nucleus
(ii) Nucleolan membrane disappear during Ana Phase stage of mitosis
(iii) The arrangement of microtubules is called to form Asters -, which is a unique feature of plant cells
(iv) One of the protein synthesis in G2 – phase is known as Maturation Promoting Factor

Answer:
a) True – False – False – True

III. Find out the correct match from the following.

Question 1.
Zygotene – Chromosomes appear as tetrads
Pachytene – Synapsis of homologous chromosomes occur
Diplotene – Condensation of chromosomes takes place
Diakinesis – Terminalisation of chiasmata occur & Nucleolus Disappear
Answer:
Diakinesis -Terminalisation of chiasmata occur & Nucleolus Disappear

Question 2.
Duration of different Phases of cell cycle given find out the correct match
(I) S Phase – 12 Hours
(II) G1 Phase – 11 Hours
(III) G2 Phase – 4 Hours
(IV) M Phase – 2 Hours
Answer:
(III) G2 Phase – 4 Hours

IV. Find out the Wrong match

Question 1.
(I) The chromosome does not divide as chromatids, for centromere does not divide – Anaphase I
(II) The chromatids move to the opposite poles by the splitting of the centromere – Anaphase
(III) Sister chromatids get separated by splitting of Centromere – Anaphase II
(IV) Homologous chromosomes appear as bivalent or tetrad – Metaphase II
Answer:
(IV) Homologous chromosomes appear as bivalent or tetrad – Metaphase II

Question 2.
Most nëurons remain in G-’o’ stage do not divide
(I) This technique can be applied to replace neurons in dementia patients
(II) neurons can be activated by giving electric shocks
(III) neurons can be replaced by surgical procedures
(IV) Dead or injured neurons can be replaced by stem cell therapy
Answer:
(IV) Dead or injured neurons can be replaced by stem cell therapy

V.

Question 1.
Match the following and find the
(I) Robert Brown – A) Coined the word cell
(II) Robert Hook – B) Coined the word Mitosis
(III) Schleiden & Schwann – C) Studied the presence of Nucleus in cells
(IV) Waither Flemming – D) Cell theory

Answer:
d) C-A- D- B

Question 2.
(I) Cell cycle – A) division that follows the nuclear division
(II) Restriction point – B) Longest part but not resting stage
(III) lnterphae – C) A series of events leading to the formation of a new Cell
(IV) Cytokinesis – D) The checkpoint at the end of Gi determine a cell’s fate

Answer:
c) C-D- B- A

VI. 

Question 1.
Read the following Assertion and Reason. Find the correct answer
Assertion A: The mitochondrial inheritance in higher animals is uniparental
Reason R: The mitochondria from the male partner either undergo degeneration or rejected and only mitochondria from egg or ova is accepted.
(a) Assertion and Reason are correct Reason is explaining assertion
(b) Assertion and Reason are correct, but the reason is not explaining assertion
(c) Assertion is true but Reason not explaining assertion
(d) Assertion is true but Reason is wrong
Answer:
a) Assertion and Reason are correct. Reason is explaining assertion

Question 2.
Assertion A: In Meiosis Prophase I is a longer but significant phase
Reason R: Chiasma formation and crossing over takes place and recombination takes place
(a) Assertion and Reason are correct Reason is explaining Assertion
(b) Assertion and Reason are correct but Reason is not explaining Assertion
(c) Assertion is true but Reason is wrong
(d) Assertion is true but Reason not explaining Assertion
Answer:
b) Assertion and Reason are correct but Reason is not explaining Assertion

Question 3.
Assertion A: Interphase is the longest part of cell division and the cell actively involved protein synthesis & DNA synthesis
Reason: The Interphase is also known as the resting phase, & the cell takes rest between successive cell division
(a) Assertion and Reason are correct Reason is explaining Assertion
(b) Assertion and Reason are correct but Reason is not explaining Assertion
(c) Assertion is true but Reason is wrong
(d) Assertion is true but Reason not explaining assertion
Answer:
c) Assertion is true but Reason is wrong

Question 4.
Assertion A: The sister chromatids of homologous chromosomes exchange chromosomal bits
Reason R: This process of exchange of chromosomal bits is known as crossing over
(a) Assertion and Reason are correct Reason is explaining Assertion
(b) Assertion and Reason are correct but Reason is not explaining Assertion
(c) Assertion is true but Reason is wrong
(d) Assertion is true but Reason not explaining assertion
Answer:
d) Assertion is true but Reason not explaining assertion

VII. 

Question 1.
See the diagram & label the parts

Answer:
A – Leptotene
B – Chromosomes are visible under a light microscope
C – Paired sister chromatids begin to condense

Question 2.
See the diagram and write the correct answer.

A	B	C	D
a) Cell growth	interphase	Mitotic phase	Cyto kinesis
b) Interphase	Cell growth	Mitotic phase	Cytokinesis
c) Cell growth	Inter Phase	Cytokinesis	Mitotic phase
d) Interphase	Cell growth	Cytokineses	Mitotic phase

Answer:
a) Cell growth – Interphase – Mitotic phase – Cyto kinesis

Question 3.
See the diagram & label Find out the correct labelling.

	A	B	C	D
a)	Chromatin	Kineto chore	See constriction	Centromere
b)	Centromere	Chromatin	See constriction	Kineto chore
c)	Centromere	Kineto chore	Chromatin	Centomere
d)	Chromatin	See Constriction	Kineto chore	Centomere

Answer:
b) Centromere – Chromatin – Secondary constriction – Kinetochore

Question 4.
Label the diagram properly.

Answer:
A – Non-sister Chromatids
B – Centromere
C – Chiasma
D – Bivalent or Tetrad

Question 5.

Answer:
A – Outer kinetochore
B – Fibrous corona
C – Inner Kinetochore
D – Microtubules

2 Mark Questions.

Question 1.
Name the two types of nuclear division.
Answer:
The two types of nuclear division:

1. Mitosis and
2. Meiosis.

Question 2.
What are the reasons for the arresting growth of cell during G1 Phase?
Answer:

• Deprivation of nutrition
• Lack of growth factors or density-dependent inhibition occur
• Some metabolic changes leads to Go – stage

Question 3.
Point out the reasons responsible for the arresting of the cell in the G₁ phase?
Answer:
Cells are arrested in G₁ due to:

• Nutrient deprivation
• Lack of growth factors or density dependant inhibition
• Undergo metabolic changes and enter into G₀ state.

Question 4.
Differentiate between karyokinesis and Cytokinesis of Amitosis.
Answer:

Karyokinesis	Cytokinesis
Division of Nucleus occur	Division of Cytoplasm occur
Nucleus develop contraction at the centre become dumbbell shaped contriction deepen divide nucleus into two	Plasma membrane develop constriction along with nuclear contraction, which deepen centripetally and the cell divides into two

Question 5.
Define amitosis & write about its drawbacks.
Answer:
Amitosis is known as Direct cell division or Incipient cell division.
No spindle formation, no condensation of chromatin material occur.

It has one 2 steps

1. Karyokinesis
2. Cytokinesis

Drawbacks: Causes unequal distribution of chromosomes Can lead to abnormalities in

• metabolism
• reproduction

Question 6.
Distinguish between Closed and Open mitosis.
Answer:

Closed mitosis	Open mitosis
Nuclear envelope remain intact & chromosomes migrate to opposite poles of a spindle with in the Nucleus Eg – Unicellular Eukaryotes – Yeast, Slime molds	Nuclear envelope breaks down and then reforms around the 2 sets of separated Chromosome Eg – Most higher Plants & Animals

Question 7.
Differentiate between Anastral and Amphiastral cell division
Answer:

Anastral	Amphiastral
Occur in plant cell No asters or centrioles are formed, only spindle fibres are formed Eg. Plants	Occur in animal cells Asters and centrioles formed at each pole of the spindle during cell division Eg. Animals

Question 8.
What happens to plant cells at the end of Telophase in Mitosis?
Answer:
In plants, phragmoplast are formed between the daughter cells. A cell plate is formed between the two daughter cells, reconstruction of cell wall takes place. Finally, the cells are separated by the distribution of organelles, macromolecules into two newly formed daughter cells.

Question 9.
Differentiate meiosis in Plants & Animals.
Answer:

Plants	Animals
In flowering plants meiosis occur during Microsporogenesis (anther) & in Mega sporogenesis (i.e) (ovule) development	It take place in reproductive organs at the time of production of gametes Spermatogenesis – produces haploid sperms Oogenesis – produces haploid eeas

Question 10.
Define Mitogens.
Answer:

• The biochemical substances or factors which promote cell cycle acceleration & proliferation is called Mitogen.
• Eg. Gibberellin, Ethylene, Indole Acelic Acid, Kinetin.
• They are also known as Growth promotors.

Question 11.
Explain briefly about Endomitosis.
Answer:
The replication of chromosomes in the absence of nuclear division and cytoplasmic division resulting in numerous copies within each cell is called endomitosis. Chromonema do not separate to form chromosomes but remain closely associated with each other. Nuclear membrane does not rupture. So no spindle formation. It occurs notably in the salivary glands of Drosophila and other flies. Cells in these tissues contain giant chromosomes (polyteny), each consisting of over thousands of intimately associated, or synapsed, chromatids. Example: Polytene chromosome.

3 Mark Questions

Question 1.
Write down the significance of Meiosis.
Answer:

• Maintain chromosome number constant
• Crossing over (exchange of genetic meterial) leads to variations
• Variation – the raw material for Evolution
• Finally, meiosis produces genetic variability by partitioning different combinations of genes into gametes through an independent assortment.
• Responsible for Adaptations of organisms to various environmental stress.

Question 2.
Differentiate between Mitosis in Plants & Animals.
Answer:

Plants	Animals
Centrioles are absent	Centrioles are present
Asters are not formed	Asters are formed
Cell division involves the formation of a cell	Cell division involves furrowing and cleavage of cytoplasm
Occurs mainly at the meristem	Occurs in tissues throughout the body

Question 3.
Explain Endomitosis.
Answer:
Sometimes, the replication of chromosomes occur in the absence of karyokinesis & cytokinesis resulting in numerous copies within each cell condition known as Endomitosis.

• Chromonema donot separate to form Chromosomes
• Nuclear membrance does not repture
• No spindle formation occur
• Each chromosome consisting of over thousands of synapsed Chromatids
  Eg – Salvary gland chromosome of Drosophila (Polytene or Chromosome).

Question 4.
Differentiate between Anaphase I & Anaphase II of Meiosis.
Answer:

5 Mark Questions

Question 1.
Explain in detail the various stages of Prophase I.
Answer:
The various stages of Prophase I:
1. Prophase I – Prophase I is of longer duration and it is divided into 5 substages – Leptotene, Zygotene, Pachytene, Diplotene and Diakinesis.

2. Leptotene – Chromosomes are visible under light microscope. Condensation of chromosomes takes place. Paired sister chromatids begin to condense.

3. Zygotene – Pairing of homologous chromosomes takes place and it is known as synapsis. Chromosome synapsis is made by the formation of synaptonemal complex. The complex formed by the homologous chromosomes are called as bivalent (tetrads).

4. Pachytene – At this stage bivalent chromosomes are clearly visible as tetrads. Bivalent of meiosis I consists of 4 chromatids and 2 centromeres. Synapsis is completed and recombination nodules appear at a site where crossing over takes place between non – sister chromatids of homologous chromosome. Recombination of homologous chromosomes is completed by the end of the stage but the chromosomes are linked at the sites of crossing over. This is mediated by the enzyme recombinase.

5. Diplotene – Synaptonemal complex disassembled and dissolves. The homologous chromosomes remain attached at one or more points where crossing over has taken place. These points of attachment where ‘X’ shaped structures occur at the sites of crossing over is called.

6. Chiasmata: Chiasmata are chromatin structures at sites where recombination has been taken place. They are specialised chromosomal structures that hold the homologous chromosomes together. Sister chromatids remain closely associated whereas the homologous chromosomes tend to separate from each other but are held together by chiasmata. This substage may last for days or years depending on the sex and organism. The chromosomes are very actively transcribed in females as the egg stores up materials for use during embryonic development. In animals, the chromosomes have prominent loops called lampbrush chromosome.

7. Diakinesis – Terminalisation of chiasmata. Spindle fibres assemble. Nuclear envelope breaks down. Homologous chromosomes become short and condensed. Nucleolus disappears.

Question 2.
Explain karyokinesis in mitosis of plant cell
Answer:

Prophase – Longest Phase

• Chromosomes visible thread like condenses into thick chromosomes
• Initiation of spindle fibres occur
• Nucleolus disappear Nuclear envelope breaks down
• Golgi apparatus & ER not seen

Metaphase

• Sister chromatids attached to spindle fibres by kinetochore of centromere
• Chromosome align on the equatorial plane (metaphase plate)
  (spindle assembly check point decide the fate of the cell)

Anaphase

• Centromere split daughter chromatids move to opposite poles
• Shortening of spindle create pull divide centromere & divide chromosome into a chromatids
  (APC /C leads to degradation of protein lead to separation of chromatids

Telophase

• Genetic material division completed Nucleolus & Nuclear membrane reform.
• Sister chromatids become thick chromosomes with its own centromere.

Question 3.
Explain S phase & G2 phase, til S Phase
Answer:
(i) S Phase:

• Known as synthetic phase of interphase of mitosis
• Growth of cell continues
• Replication of DNA occur
• Histones synthesised and attach to DNA
• Duplication of centrioles occur
• DNA content doubles from 2C to 4C

(ii) G2 phase

• 4 C amount of DNA
• Cell growth continues
• Synthesis of
  • organelle,
  • mitochondria & chloroplast
  • tubulin synthesised, microtubules formed
• Spindle begin to occur
• Nuclear division follows
• MPF (Maturation Promoting factor) formed brings out condensation of interphase chromosomes into mitotic form.

Question 4.
Draw the Cell cycle.
Answer:

Question 5.
What are the significances of Mitosis.
Answer:
Exact copy of the parent cell is produced by mitosis (genetically identical).

1. Genetic stability – Daughter cells are genetically identical to parent cells.
2. Growth – As multicellular organisms grow, the number of cells making up their tissue increases. The new cells must be identical to the existing ones.
3. Repair of tissues – Damaged cells must be replaced by identical new cells by mitosis.
4. Asexual reproduction – Asexual reproduction results in offspring that are identical to the parent. Example Yeast and Amoeba.
5. In flowering plants, structure such as bulbs, corms, tubers, rhizomes and runners are produced by mitotic division. When they separate from the parent, they form a new individual. The production of large numbers of offsprings in a short period of time, is possible only by mitosis. In genetic engineering and biotechnology, tissues are grown by mitosis (i.e. in tissue culture).
6. Regeneration – Arms of starfish

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Physics Guide Pdf Chapter 11 Waves Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Physics Solutions Chapter 11 Waves

11th Physics Guide Waves Book Back Questions and Answers

I. Multiple choice questions:

Question 1.
A student tunes his guitar by striking a 120 Hertz with a tuning fork, and simultaneously plays the 4^th string on his guitar. By keen observation, he hears the amplitude of the combined sound oscillating thrice per second. Which of the following frequencies is the most likely the frequency of the 4th string on his guitar?
(a) 130
(b) 117
(c) 110
(d) 120
Answer:
(b) 117

Hint:
Frequency of the fourth string can be derived from harmonic series generated by the strings.
Frequencies of first 4 strings are 120, 119, 118, 117 Hz.
f₄ = 117Hz

Question 2.
A transverse wave moves from a medium A to a medium B. In medium A, the velocity of the transverse wave is 500 ms^-1 and the wavelength is 5 m. The frequency and the wavelength of the wave in medium B when its velocity is 600 ms^-1, respectively are:
(a) 120 Hz and 5 m
(b) 100 Hz and 5 m
(c) 120 Hz and 6 m
(d) 100 Hz and 6 m
Answer:
(d) 100 Hz and 6 m

Hint:
v_A = 500 ms^-1; λ_A = 5 m
∴ Frequency in medium B
f_B = \(\frac{v_{\mathrm{A}}}{\lambda_{\mathrm{A}}}\) = \(\frac { 500 }{ 5 }\) = 100 Hz
Wavelength in medium B is
λ_B = \(\frac{v_{\mathrm{B}}}{f_{\mathrm{B}}}\) = \(\frac { 600 }{ 100 }\) = 6m

Question 3.
For a particular tube, among six harmonic frequencies below 1000 Hz, only four harmonic frequencies are given: 300 Hz, 600 Hz, 750 Hz and 900 Hz. What are the two other frequencies missing from this list?
(a) 100 Hz, 150 Hz
(b) 150 Hz, 450 Hz
(c) 450 Hz, 700 Hz
(d) 700 Hz, 800 Hz
Answer:
(b) 150 Hz, 450 Hz

Hint: Fundamental frequency f₀ = 150 Hz
From the series of frequencies we get
f₁ = 2f₀
f₂ = 3f₀
= 3 x 150
= 450 Hz

Question 4.
Which of the following options is correct?

Options for (1), (2) and (3), respectively are:
(a) (b), (c) and (a)
(b) (c), (a) and (b)
(c) (a), (b) and (c)
(d) (b), (a) and (c)
Answer:
(a) (b), (c) and (a)

Question 5.
Compare the velocities of the wave forms given below, and choose the correct option.

where, v_A, v_B, v_C and v_D are velocities given in (a), (b), (c) and (d), respectively.
(a) v_A > v_B > v_D > v_C
(b) v_A < v_B < v_D < v_C
(c) v_A = v_B = v_D = v_C
(d) v_A > v_B = v_D > v_C
Answer:
(c) v_A = v_B = v_D = v_C

Hint:
The amplitude of the velocity waves is same in all four cases.

Question 6.
A sound wave whose frequency is 5000 Hz travels in air and then hits the water surface. The ratio of its wavelengths in water and air is:
(a) 4.30
(b) 0.23
(c) 5.30
(d) 1.23
Answer:
(a) 4.30

Hint:
Frequency = 5000 Hz
Speed of sound in air v_air = 332 m/s
Speed of sound in water v_water = 1450 m/s

Question 7.
A person standing between two parallel hills fires a gun and hears the first echo after t₁ sec and the second echo after t₂ sec. The distance between the two hills is:
(a) \(\frac{v\left(t_{1}-t_{2}\right)}{2}\)
(b) \(\frac{v\left(t_{1} t_{2}\right)}{2\left(t_{1}+t_{2}\right)}\)
(c) v(t₁ + t₂)
(d) \(\frac{v\left(t_{1}+t_{2}\right)}{2}\)
Answer:
(d) \(\frac{v\left(t_{1}+t_{2}\right)}{2}\)

Hint:
For first echo 2d₁ = vt₁
For second echo 2d₂ = vt₂
∴ d = d₁ + d₂ = \(\frac{v\left(t_{1}+t_{2}\right)}{2}\)

Question 8.
An air column in a pipe which is closed at one end, will be in resonance with the vibrating body of frequency 83 Hz. Then the length of the air column is:
(a) 1.5 m
(b) 0.5 m
(c) 1.0 m
(d) 2.0 m
Answer:
(c) 1.0 m

Hint:
l = \(\frac { λ }{ 4 }\); f = 83 Hz
v = 332 m/s
λ = \(\frac { v }{ f }\)
= \(\frac { 332 }{ 83 }\)
= 4 m
l = \(\frac { λ }{ 4 }\) = \(\frac { 4m }{ 4 }\) = 1m = 1.0 m

Question 9.
The displacement y of a wave travelling in the x direction is given by y = (2 x 10^-3) sin (300t – 2x + \(\frac { π }{ 4 }\)), where x and y are measured in metres and t in second. The speed of the wave is:
(a) 150 ms^-1
(b) 300 ms^-1
(c) 450 ms^-1
(d) 600 ms^-1
Answer:
(a) 150 ms^-1

Hint:
The given equation is similar to

Question 10.
Consider two uniform wires vibrating simultaneously in their fundamental notes. The tensions, densities, lengths and diameter of the two wires ,are in the ratio 8:1, 1:2, (x : y) and 4 : 1 respectively. If the note of the higher pitch has a frequency of 360 Hz and the number of beats produced per second is 10, then the value of (x : y) is:
(a) 36 : 35
(b) 35 : 36
(c) 1 : 1
(d) 1 : 2
Answer:
(a) 36 : 35

Hint:
No. of beats = 10
Frequency of higher pitch f₁ = 360 Hz
Frequency of lower pitch f₂ = 360 – 10 = 350 Hz
x : y = Ratio of length
l ∝ f
l₁ : l₂ = x : y = f₁ : f₂
= 360 : 350
= 36 : 35

Question 11.
Which of the following represents a wave:
(a) (x – vt)³
(b) x(x + vt)
(c) \(\frac { 1 }{ (x +vt) }\)
(d) sin(x + vt)
Answer:
(d) sin(x + vt)

Hint:
Wave must have a wave function.
Since y = a sin ωt

Question 12.
A man sitting on a swing which is moving to an angle of 60° from the vertical is blowing . a whistle which has a frequency of 2.0 k Hz. The whistle is 2.0 m from the fixed support point of the swing. A sound detector which detects the whistle sound is kept in front of the swing. The maximum frequency the sound detector detected is:
(a) 2.027 kHz
(b) 1.914 kHz
(c) 9.14 kHz
(d) 1.011 kHz
Answer:
(a) 2.027 kHz

Hint:

Question 13.
Let y = \(\frac{1}{1+x^{2}}\) at t = 0 be the amplitude of the wave propagating in the positive x-direction. At t = 2s, the amplitude of the wave propagating becomes y = \(\frac{1}{1+(x-2)^{2}}\). Assume that the shape of the wave does not
change during propagation. The velocity of the wave is:
(a) 0.5 ms^-1
(b) 1.0 ms^-1
(c) 1.5 ms^-1
(d) 2.0 ms^-1
Answer:
(b) 1.0 ms^-1

Hint:

Question 14.
A uniform rope having mass m hangs vertically from a rigid support. A transverse wave pulse is produced at the lower end. Which of the following plots shows the correct variation of speed v with height h from the lower end?

Answer:

Hint:
Speed varies exponentially with height h.

Question 15.
An organ pipe A closed at one end is allowed to vibrate in its first harmonic and another pipe B open at both ends is allowed to vibrate in its third harmonic. Both A and B are in resonance with a given tuning fork. The ratio of the length of A and B is:
(a) \(\frac { 8 }{ 3 }\)
(b) \(\frac { 3 }{ 8 }\)
(c) \(\frac { 1 }{ 6 }\)
(d) \(\frac { 1 }{ 2 }\)
Answer:
(d) \(\frac { 1 }{ 2 }\)

Hint:
First harmonic of a closed organ pipe
L_C = \(\frac { 3 λ }{ 4 }\)
Third harmonic of an open organ pipe
L₀ = \(\frac { 3 λ }{ 2 }\)
\(\frac{\mathrm{L}_{\mathrm{C}}}{\mathrm{L}_{\mathrm{O}}}\) = \(\frac { 3 π }{ 4 }\) x \(\frac { 3 }{ 3λ }\)
= \(\frac { 2 }{ 4 }\)
= \(\frac { 1 }{ 2 }\)
∴ \(\frac{\mathrm{L}_{\mathrm{C}}}{\mathrm{L}_{\mathrm{O}}}\) = \(\frac { 1 }{ 2 }\)

II. Short Answer Questions:

Question 1.
What is meant by waves?
Answer:
The disturbance which carries energy and momentum from one point in space to another point in space without the transfer of the medium is known as a wave.

Question 2.
Write down the types of waves.
Answer:
Waves can be classified into two types –

• Transverse waves
• Longitudinal waves

Question 3.
What are transverse waves? Give one example.
Answer:
In transverse wave motion, the constituents of the medium oscillate or vibrate about their mean positions in a direction perpendicular to the direction of propagation (direction of energy transfer) of waves.
Example: light (electromagnetic waves)

Question 4.
What are longitudinal waves? Give one example.
Answer:
The direction of vibration of particles in a medium is parallel to the direction of propagation of the wave.
Example: Sound waves traveling in air.

Question 5.
Define wavelength.
Answer:
For transverse waves, the distance between two neighbouring crests or troughs is known as the wavelength. For longitudinal waves, the distance between two neighbouring compressions or rarefactions is known as the wavelength. The SI unit of wavelength is meter.

Question 6.
Write down the relation between frequency, wavelength and velocity of a wave.
Answer:
Velocity of the wave is v = λf.

Question 7.
What is meant by the interference of waves?
Answer:
Interference is a phenomenon in which two waves moving in the same direction superimpose to form a resultant wave of greater, lower or the same amplitude.

Question 8.
Explain the beat phenomenon.
Answer:
When two or more waves superimpose each other with slightly different frequencies, then a sound of periodically varying amplitude at a point is observed. This phenomenon is known as beats. The number of amplitude maxima per second is called beat frequency. If we have two. sources, then their difference in frequency gives the beat frequency. Number of beats per second n = |f₁ – f₂| per second

Question 9.
Define intensity of sound and loudness of sound.
Answer:
“Loudness is defined as the degree of the sensation of sound produced in the ear or the perception of sound by the listener”. The intensity of sound is defined as “the sound power transmitted per unit area placed normal to the propagation of sound wave”.

Question 10.
Explain Doppler Effect.
Answer:
When the source and the observer are in relative motion with respect to each other and to the medium in which sound propagates, the frequency of the sound wave observed is different from the frequency of the source. This phenomenon is called Doppler Effect.

Question 11.
Explain red. shift and blue shift in Doppler Effect.
Answer:
If the spectral lines of the star are found to shift towards red end of the spectrum (called redshift) then the star is receding away from the Earth. If the spectral lines of the star are found to shift towards the blue end of the spectrum (called blue shift) then the star is approaching Earth.

Question 12.
What is meant by end correction in resonance air column apparatus?
Answer:
Since the antinodes are not exactly formed at the open end, we have to include a correction, called end correction e. It is calculated, by assuming that antinode is formed at a small distance above the open end e = 0.3 d.

Question 13.
Sketch the function y = x + a. Explain your sketch.
Answer:

Question 14.
Write down the factors affecting velocity of sound in gases.
Answer:
(i) Effect of pressure: Speed of sound is independent of pressure for a fixed temperature.

(ii) Effect of temperature: Speed of sound varies directly to the square root of temperature in kelvin. Speed of sound in air increases by 0.61 ms^-1 per degree celcius rise in temperature.

(iii) Effect of density: Velocity of sound in a gas is inversely proportional to the square root of the density of the gas.

(iv) Effect of moisture (humidity): Speed of sound increases with rise in humidity.

(v) Effect of wind: In the direction along the wind blowing, the speed of sound to wind blowing, the speed of sound decreases.

Question 15.
What is meant by an echo? Explain.
Answer:
An echo is a repetition of sound produced by the reflection of sound waves from a wall, mountain or other obstructing surfaces. The minimum distance from a sound-reflecting wall to hear an echo at 20°C is 17.2 meter.

III. Long Answer Questions:

Question 1.
Discuss how ripples are formed in still water.
Answer:
Suppose we drop a stone in a trough of still water, we can see a disturbance produced at the place where the stone strikes the water surface. We find that this disturbance spreads out (diverges out) in the form of concentric circles of ever-increasing radii (ripples) and strikes the boundary of the trough. This is because some of the kinetic energy of the stone is transmitted to the water molecules on the surface.

Actually, the particles of the water (medium) themselves do not move outward with the disturbance. This can be observed by keeping a paper strip on the water surface. The strip moves up and down when the disturbance (wave) passes on the water surface. This shows that the water molecules only undergo vibratory motion about their mean positions.

Question 2.
Briefly explain the difference between traveling waves and standing waves.
Answer:
Progressive waves:

1. Crests and troughs ate formed in transverse progressive waves. Compression and rarefaction are formed in longitudinal progressive waves. These waves move forward or backward in a medium i.e., they will advance in a medium with a definite velocity.
2. All the particles in the medium vibrate in such a way that the amplitude of the vibration for all particles is the same.
3. These waves carry energy while propagating.

Stationary waves:

1. Crests and troughs are formed in transverse stationary waves. Compression and rarefaction are formed in longitudinal stationary waves. These waves neither move forward nor backward in a medium i.e., they will not advance in a medium.
2. Except at nodes, all other particles of the medium vibrate such that the amplitude of vibration is different for different particles. The amplitude is minimum or zero at nodes and maximum at antinodes.
3. These waves do not transport energy.

Question 3.
Show that the velocity of a traveling wave produced in a string is v = \(\sqrt{\frac{T}{\mu}}\)
Answer:
Let us consider an elemental segment in the string as shown in the Figure. Let A and B be two points on the string at an instant of time. Let dl and dm be the length and mass of the elemental string, respectively. By definition, linear mass density, μ is

μ = \(\frac { dm }{ dl }\) … (1)
dm = μ dl … (2)
Consider an elemental string AB having a curvature which looks like an arc of a circle with centre at O, radius R and the arc subtending an angle θ at the origin O as shown in Figure. The angle 0 can be written in terms of arc length and radius as \(\frac { dl }{ R }\) = θ. The centripetal acceleration supplied by the tension in the string is
a_cp = \(\frac{v^{2}}{\mathrm{R}}\) … (3)
Then, centripetal force can be obtained when mass of the string (dm) is included in equation (3)
F_cp = \(\frac{(dm)v^{2}}{\mathrm{R}}\) … (4)
Experienced by elemental string can be calculated by substituting equation (2) in equation (4) we get the centripetal force as
\(\frac{(dm)v^{2}}{\mathrm{R}}\) = \(\frac{\mu v^{2} d l}{R}\) … (5)
The tension T acts along the tangent of the elemental segment of the string at A and B. Since the arc length is very small, variation in the tension force can be ignored. T can be resolved into horizontal component T cos (\(\frac { θ }{ 2 }\)) and vertical component T sin (\(\frac { θ }{ 2 }\)).

The horizontal components at A and B are equal in magnitude but opposite in direction. Hence, they cancel each other. Since the elemental arc length AB is taken to be very small, the vertical components at A and B appears to acts vertical towards the centre of the arc and hence, they add up. The net radial force F_r is
F_r = 2Tsin(\(\frac { θ }{ 2 }\)) … (6)
Since the amplitude of the wave is very small when it is compared with the length of the string, the sine of small angle is approximated
as sin (\(\frac { θ }{ 2 }\)) ≈ \(\frac { θ }{ 2 }\). Hence, equation (6) can be written as,
F_r = 2T x \(\frac { θ }{ 2 }\) = Tθ … (7)
But θ = \(\frac { dl }{ R }\), therefore substituting in equation (7), we get
F_r = T \(\frac { dl }{ R }\) … (8)
Applying Newton’s second law to the elemental string in the radial direction, under equilibrium, the radial component of the force is equal to the centripetal force. By equating equation (5) and equation (8), we get,
T \(\frac { dl }{ R }\) = μv²dl
v = \(\sqrt{\frac{\mathrm{T}}{\mu}}\) measured in ms^-1

Question 4.
Describe Newton’s formula for velocity of sound waves in air and also discuss the Laplace’s correction.
Answer:
Newton assumed that when sound propagates in air, the formation of compression and rarefaction takes place in a very slow manner so that the process is isothermal in nature. It is found that, the heat produced during compression (pressure increases, volume decreases), and heat lost during rarefaction (pressure decreases, volume increases) occur over a period of time such in a way that the temperature of the medium remains constant. Hence, by treating the air molecules to form an ideal gas, the changes in pressure and volume obey Boyle’s law, Mathematically
PV= Constant …(1)
Differentiating equation (1), we get
PdV + Vdp = 0
(or) P = – V\(\frac { dp }{ dv }\) = B_T … (2)
where, B_T is an isothermal bulk modulus of air.
v = \(\sqrt{\frac{\mathrm{B}}{\rho}}\) … (3)
Substituting equation (2) in equation (3), the speed of sound in air is
v_T = \(\sqrt{\frac{\bar{B}_{\mathrm{T}}}{\rho}}\) = \(\sqrt{\frac{\mathrm{P}}{\rho}}\)
Since P is the pressure of air whose value at NTP (Normal Temperature and Pressure) is 76 cm of mercury, we have
P = (0.76 x 13.6 x 10³ x 9.8)Nm^-2
ρ = 1.293 kg m^-3.
Here p is density of air. Then the speed of sound in air at normal temperature and pressure (NTP) is

But the speed of sound in air at 0°C is experimentally observed as 332 ms^-1 that is close up to 16% more than theoretical value.

Laplace correction: Laplace satisfactorily corrected this discrepancy by assuming that when the sound propagates through a medium, the particles oscillate very rapidly such that the compression and rarefaction occur very fast. Hence the exchange of heat produced due to compression and cooling effect due to rarefaction do not take place, because, air (medium) is a poor conductor of heat. Since, temperature is no longer considered as a constant here, propagation of sound is an adiabatic process. By adiabatic considerations, the gas obeys Poisson’s law (not Boyle’s law as Newton assumed), that is
PV’ = Constant … (4)
where, γ = \(\frac{\mathrm{C}_{\mathrm{p}}}{\mathrm{C}_{\mathrm{v}}}\), that is the ratio between specific heat at constant pressure and specific heat at constant volume.
Differentiating equation (4) on both the sides, we get
V^γ dP + P (γV^γ-1 dV) = 0
or, γP = – V\(\frac { dp }{ dv }\) = B_A … (5)
where, B_A is the adiabatic bulk modulus of air.
v = \(\sqrt{\frac{\mathrm{B}}{\rho}}\)
Now, substituting equation (5) in equation (6), the speed of sound in air is

Since air contains mainly, nitrogen, oxygen, hydrogen etc, (diatomic gas), we take γ = 1.47. Hence, speed of sound in air is v_A = (\(\sqrt{1.4}\))(280ms^-1) = 331.30 ms^-1, which is very much closer to experimental data.

Question 5.
Write short notes on reflection of sound waves from plane and curved surfaces.
Answer:
When the sound waves hit the plane wall, they bounce off in a manner similar to that of light. When a loudspeaker is kept at an angle with respect to a wall (plane surface), then the waves coming from the source (assumed to be a point source) can be treated as spherical wave fronts. Hence, the reflected wave front on the plane surface is also spherical, such that its centre of curvature can be treated as the image of the sound source (virtual or imaginary loud speaker) that can be assumed to be at a position behind the plane surface. These are shown in figures.

The behaviour of sound is different when it is reflected from different surfaces-convex or concave or plane. The sound reflected from a convex surface is spread out and so it is easily attenuated and weakened. Whereas, if it is reflected from the concave surface it will converge at a point and this can be easily amplified. The parabolic reflector (curved reflector) that is used to focus the sound precisely to a point is used in designing the parabolic mics which are known as high directional microphones.

We know that any surface (smooth or rough) can absorb sound. For instance, the sound produced in a big hall or auditorium or theatre is absorbed by the walls, ceilings, floor, seats etc. To avoid such losses, a curved sound board (concave board) is kept in front of the speaker, in such a way that the board reflects the sound waves of the speaker towards the audience. This method will minimize the spreading of sound waves in all possible direction in that hall it also enhances the uniform distribution of sound throughout the hall. Hence a person sitting at any position in that hall can hear the sound without any disturbance.

Question 6.
Briefly explain the concept of the superposition principle.
Answer:
When two or more waves in a medium overlap, their total displacement is the vector sum of the individual displacements.
Let us consider two functions which characterize the displacement of the waves, for example,
y₁ = A₁ sin(kx – ωt)
and y₂ = A₂ sin(kx – ωt)
Since both y₁ and y₂ satisfy the wave equation (solutions of wave equation) then their algebraic sum
y = y₁ + y₂
also satisfies the wave equation. It is meant that the displacements are additive.

Question 7.
Explain how the interference of waves is formed.
Answer:
Interference is a phenomenon in which two waves superimpose to form a resultant wave of greater, lower, or the same amplitude.

Let us consider two harmonic waves having identical frequencies, constant phase difference φ, and same waveform (can be treated as coherent source), but having amplitudes A₁ and A₂, then
y₁ = A₁ sin(kx – ωt) … (1)
y₂ = A₂ sin(kx – ωt) … (2)
Suppose they move simultaneously in a particular direction, then interference occurs (i.e., the overlap of these two waves). Mathematically y = y₁ + y₂ … (3)
Hence by substituting equation (1) and equation (2) in equation (3), we get

By squaring and adding equation (5) and (6), we get,
A² = A₁² + A₂² + 2A₁A₂cosφ … (8)
Since, intensity is square of the amplitude (I – A²), we get,
I = I₁ + I₂ + 2\(\sqrt{\mathrm{I}_{1} \mathrm{I}_{2}} \cos \varphi\) … (9)
This means the resultant intensity at any point depends on the phase difference at that point.

Question 8.
Describe the formation of beats.
Answer:
When two or more waves superimpose each other with slightly different frequencies, then a sound having periodically varying amplitude at a point is observed. This phenomenon is known as beats. The number of amplitude maxima per second is called beat frequency. If we have two sources, then their difference in frequency gives the beat frequency.
Number-of beats per second
n = \(\left|f_{1}-f_{2}\right|\) Per second

Question 9.
What are stationary waves? Explain the formation of stationary waves and also write down the characteristics of stationary waves.
Answer:
When the wave hits the rigid boundary it bounces back to the original medium and can interfere with the original waves. A pattern is formed, that is known as standing waves or waves stationary. Let us consider two harmonic progressive waves (formed by strings) that have the same amplitude and same velocity but move in opposite directions. Then the displacement of the first wave (incident wave) is
y₁ = A sin(kx – ωt) … (1)
(waves move toward right)
The displacement of the second wave (reflected wave) is
y₂ = A sin(kx + ωt) … (2)
(waves move toward left)
both will interfere with each other by the principle of superposition, the net displacement is
y = y₁ + y₂ … (3)
By substituting equation (1) and equation (2) in equation (3), we get
y = \(\left\{\begin{array}{l}
\mathrm{A} \sin (k x-\omega t) \\
+\mathrm{A} \sin (k x+\omega t)
\end{array}\right.\) … (4)
Using trigonometric identity, we rewrite equation (4) as
y(x, t) = 2A cos(ωt) sin(kx) … (5)
This represents a stationary wave or standing wave, It is meant that this wave does not move either forward or backward, whereas progressive or travelling waves will move forward or backward. In addition, the displacement of the particle in equation (5) can be written in more compact form,
y(x, t) = A’cos(cot)
where, A’ = 2A sin(Ax). It is implied implying that the particular element of the string executes simple harmonic motion with amplitude equals to A’. The maximum of this amplitude occurs at positions for which
sin(kx) = 1
⇒ kx = \(\frac { π }{ 2 }\), \(\frac { 3π }{ 2 }\), \(\frac { 5π }{ 2 }\), … = nπ
where m takes half-integer or half-integral values. The position of maximum amplitude is known as an antinode. Expressing wave number in terms of wavelength, let us represent the anti-nodal positions as
x_m = (\(\frac { 2m+1 }{ 2 }\)) \(\frac { λ }{ 2 }\) … (6)
where, m = 0, 1, 2 ….
For m = 0 we have maximum at
x₀ = \(\frac { λ }{ 2 }\)
For m = 1 we have maximum at
x₀ = \(\frac { 3λ }{ 4 }\)
For m = 2 we have maximum at
x₂ = \(\frac { 5λ }{ 4 }\)
and so on.
The distance between two successive antinodes can be computed by,

Similarly, the minimum of the amplitude A’ also occurs at some points in the space, and these points can be determined by setting
sin(kx) = 0
⇒ kx = 0, π, 2π, 3π, … = nπ
where n takes integer or integral values. It is noted that the elements at these points do not vibrate (not move), and the points are called nodes. The n^th nodal positions is given by,
x_n = n\(\frac { λ }{ 2 }\) … (7)
where, n = 0, 1, 2, …
For n = 0 we have minimum at
x_o = 0
For n = 1 we have minimum at
x₁ = \(\frac { λ }{ 2 }\)
For n = 2 we have maximum at
x₂ = λ
and so on.
The distance between any two successive nodes can be calculated as
x_n – x_n-1 – n\(\frac { λ }{ 2 }\) – (n-1)\(\frac { λ }{ 2 }\) = \(\frac { λ }{ 2 }\)

Characteristics of stationary waves:

• Stationary waves are characterized by the confinement of a wave disturbance between two rigid boundaries. It is meant that the wave does not move forward or backward in a medium (does not advance), it remains steady at its place. Hence, they are called “stationary waves or standing waves”.
• Certain points in the region in which the wave exists have maximum amplitude, called anti-nodes. At certain points, the amplitude is minimum or zero, called nodes.
• The distance between two consecutive nodes (or) anti-nodes is \(\frac { λ }{ 2 }\).
• The distance between a node and its neighboring anti-node is \(\frac { λ }{ 4 }\).
• The transfer of energy along the standing wave is zero.

Question 10.
Discuss the law of transverse vibrations in stretched strings.
Answer:
There are three laws of transverse vibrations of stretched strings that are given as follows:
(i) The law of length: For a given wire with tension T (which is fixed) and mass per unit length µ. (fixed) the frequency varies inversely with the vibrating length. Therefore,
f ∝ \(\frac { 1 }{ f }\) ⇒ f = \(\frac { C }{ l }\)
⇒ l x f = C, when C is a constant.

(ii) The law of tension: For a given vibrating length l (fixed) and mass per unit length µ (fixed) the frequency varies directly with the square root of the tension T,
f ∝ \(\sqrt{T}\)
⇒ f = A\(\sqrt{T}\), when A is a constant.

(iii) The law of mass: For a given vibrating length l (fixed) and tension T (fixed) the frequency varies inversely with the square root of the mass per unit length μ,
f ∝ \(\frac{1}{\sqrt{\mu}}\) when B is a constant.

Question 11.
Explain the concepts of frequency, harmonics and detail.
Answer:
(i) The fundamental frequency is the lowest natural frequency.

(ii) If natural frequencies are written as integral multiples of the fundamental frequency, then the frequencies are said to be in harmonics. So, the first harmonic is v₁ = v₁, (the fundamental frequency is called first harmonics), the second harmonics is v₂ = 2v₁ the third harmonics is v₃ = 3v_1, and so on.

(iii) The frequency higher than the fundamental frequency can be produced by blowing air strongly at the open end. Such frequencies are called overtones.

First overtone, (f₂ = 3f₁) since here, the frequency is three times the fundamental frequency it is called third harmonic. Second overtone, (f₃ = 5f₁) and since n = 5 here, this is called fifth harmonic.

Question 12.
What is a sonometer? Give its construction and working. Explain how to determine the frequency of tuning fork using a sonometer.
Answer:
Sonometer is used for sound-related measurements. Using this device, The following quantities can be determined.
(i) The frequency of the tuning fork or frequency of the alternating current.
(ii) The tension in the string.
(iii) The unknown hanging mass.

Construction: The sonometer is made up of a hollow box that is one meter long with a uniform metallic thin string attached to it. One end of the string is connected to a hook and the other end is connected to a weight hanger through a pulley as shown in Figure. Since only one string is used, it is also known as monochord. The weights are added to the free end of the wire to increase the tension of the wire. Two adjustable wooden knives are put over the board, and their positions are adjusted to change the vibrating length of the stretched wire.

Procedure: A transverse stationary or standing wave is produced. So, at the knife edges P and Q, nodes are formed. In between the knife edges, anti-nodes are formed.
If the length of the vibrating element is l then
l = \(\frac { λ }{ 2 }\) ⇒ λ = 2l
Let f be the frequency of the vibrating element, T the tension in the string, and p the mass per unit length of the string.
Then using the the equation v = \(\sqrt{\frac{\mathrm{T}}{\mu}}\) measured in ms^-1, we get,
f = \(\frac { v }{ λ }\) = \(\frac { 1 }{ 2l }\)\(\sqrt{\frac{\mathrm{T}}{\mu}}\) in Hertz.
Let ρ be the density of the material of the string and d be the diameter of the string. Then the mass per unit length μ,

Question 13.
Write short notes on intensity and loudness.
Answer:
The intensity of sound is defined as “the sound power transmitted per unit area taken normal to the propagation of the sound wave”. The intensity of sound is inversely proportional to the square of the distance from the source.

This is known as the inverse square law of sound intensity. Two sounds with the same intensities need not have the same loudness. For example, the sound heard during the explosion of balloons in a silent closed room is very loud when compared to the same explosion happening in a noisy market.

If the intensity of sound is increased then loudness also increases. Loudness depends on both intensities of the sound wave and sensitivity of the ear.

Question 14.
Explain how overtones are produced in a,
(a) closed organ pipe
(b) Open organ pipe
Answer:
(a) Closed organ pipes: If one end of a pipe is closed, the wave reflected at this closed-end is 180° out of phase with the incoming wave. So, there is no displacement of the particles at the closed end. Hence, nodes are formed at the closed end and anti-nodes are formed at the open end.

Consider the simplest mode of vibration of the air column called the fundamental mode. Anti-node is formed at the open end and node at the closed end. From the above figure, let L be the length of the tube and the wavelength of the wave produced. For the fundamental mode of vibration, we have,
– L = \(\frac{\lambda_{1}}{4}\) (or)
Wave length λ₁ = 4L
The frequency of the note emitted is
f₁ = \(\frac{v}{\lambda_{1}}\) = \(\frac { v }{ 4L }\)
which is called the fundamental note.
The frequencies higher than the fundamental frequency can be produced by blowing air strongly at the open end. Such frequencies are called overtones.
The second mode of vibration in open pipes is shown in the figure.

is called the first overtone, since here, the frequency is three times the fundamental frequency it is called third harmonic. The Figure shows the third mode of vibration having three nodes and three anti-nodes.

is called the second overtone, and since n = 5 here, this is called fifth harmonic. Hence, the closed organ pipe has only odd harmonics and the frequency of the n^th harmonic is f_n = (2n+l)f₁. Hence, the frequencies of harmonics are in the ratio,
f₁ : f₂ : f₃ : f₄ = 1 : 3 : 5 : 7 : …

(b) Open organ pipes:
The flute is an example of an open organ pipe. It is a pipe with both ends are opened. At both open ends, anti-nodes are formed. Consider the simplest mode of vibration of the air column called fundamental mode. Since anti-nodes are formed at the open end, a node is formed at the mid-point of the pipe.

From above Figure, if L be the length of the tube, the wavelength of the wave produced is given by
L=\(\frac{\lambda_{1}}{2}\) (or) λ₁ = 2L
The frequency of the note emitted is
f₁ = \(\frac{v}{\lambda_{1}}\) = \(\frac { v }{ 2L }\)
That is called the fundamental note.
The frequencies higher than the fundamental frequency can be produced by blowing air strongly at one of the open ends. Such frequencies are called overtones.

The second mode of vibration in open pipes is shown in figure. It has two nodes and three anti-nodes,
∴ L = λ₂ (or) λ₂ = L
The frequency,
f₂ = \(\frac{v}{\lambda_{2}}\) = \(\frac { v }{ L }\) = 2 x \(\frac { v }{ 2L }\) = 2f₁
is called first over tone. Since n = 2 here, it is called the second harmonic.

The Figure above shows the third mode of vibration having three nodes and four anti-nodes
∴ L = \(\frac { 3 }{ 2 }\)λ₃ (or) λ₃ = \(\frac { 2L }{ 3 }\)
The frequency,
f₃ = \(\frac{v}{\lambda_{3}}\) = \(\frac { 3v }{ 2L }\) = 3₁
is called second over tone. Since n = 3 here, it is called the third harmonic.
Hence, the open organ pipe has all the harmonics, and the frequency of the n^th harmonic is f_n = nf₁.
Hence, the frequencies of harmonics are in the ratio f₁ : f₂ : f₃ : f₄ = 1 : 2 : 3 : 4 : …

Question 15.
How will you determine the velocity of sound using the resonance air column apparatus?
Answer:

The resonance air column apparatus is used to measure the speed of sound in air at room temperature.

Construction:
(i) It consists of a cylindrical glass tube of one-meter length whose one end A is open and another end B is connected to the water reservoir R through a rubber tube as shown in Figure.

(ii) This cylindrical glass tube is mounted on a vertical stand with a scale attached to it. The tube is partially filled with water and the water level can be adjusted by raising or lowering the water in the reservoir R.

(iii) The surface of the water will act as a closed-end and others as the open end. Hence, it behaves like a closed organ pipe, forming nodes at the surface of water and antinodes at the closed end.

(iv) When a vibrating tuning fork is brought near the open end of the tube, longitudinal waves are formed inside the air column.

(v) These waves move downward as shown in Figure, and reach the surfaces of water and get reflected and produce standing waves.

(vi) The length of the air column is varied by changing the water level until a loud sound is produced in the air column.

(vii) At this particular length the frequency of waves in the air column resonates with the frequency of the tuning fork (natural frequency of the tuning fork).

(viii) At resonance, the frequency of sound waves produced is equal to the frequency of the tuning fork. This will occur only when the length of the air column is proportional to (\(\frac { 1 }{ 4 }\))^th of the wavelength of the sound waves produced. \(\frac { 1 }{ 4 }\)λ = L₁ … (1)
But since the antinodes are not exactly formed at the open end, a Correction is to include. It is called end correction e, by assuming that the antinode is formed at some small distance above the open end. Including this end correction, the first resonance is \(\frac { 1 }{ 4 }\)λ = L₁ + e … (2)
Now the length of the air column is increased to get the second resonance. Let L₂ be the length at which the second resonance occurs. Again taking end correction into account, we have
\(\frac { 3 }{ 4 }\)λ = L₂ + e … (3)
In order to avoid end correction, let us make the difference of equation (3) and equation (2), we get
\(\frac { 3 }{ 4 }\)λ – \(\frac { 1 }{ 4 }\)λ = (L₂ + e) – (L₁ + e)
⇒ \(\frac { 1 }{ 2 }\)λ = L₂ – L₁ = ∆L
⇒ λ = 2∆L
The speed of the sound in air at room temperature can be calculated by using the formula
v = fλ = 2f∆L.

Question 16.
What is meant by the Doppler effect? Discuss the following cases.
(i) Source in motion and Observer at rest

• Source moves towards the observer
• Source moves away from the observer

(ii) Observer in motion and Source at rest.

• The observer moves towards Source
• Observer resides away from the Source

(iii) Both are in motion

• Source and Observer approach each other
• Source and Observer resides from each other
• Source chases Observer
• Observer chases Source

Answer:
When the source and the observer are in relative motion with respect to each other and to the medium in which sound is propagated, the frequency of the sound wave observed is different from the frequency of the source. This phenomenon is called Doppler Effect.

(i) Source in motion and the observer at rest:
(a) Source moves towards die observer:

Suppose a source S moves to the right (as shown in Figure) with a velocity v_s and let the frequency of the sound waves produced by the source be f_s. It is assumed that the velocity of sound in a medium is v.

The compression (sound wavefront) produced by the source S at three successive instants of time are shown in the Figure. When S is at position x₁ the compression is at C₁. When S is at position x₂, the compression is at C₂ and similarly for x₃ and C₃.

It is assumed that if C₁ reaches the observer’s position A then at that instant C₂ reaches point B and C₃ reaches point C as shown in the Figure. Obviously it is seen that the distance between compressions C₂ and C₃ is shorter than the distance between C₁ and C₂.

It is meant that the wavelength decreases when the source S moves towards the observer O. But frequency is inversely related to wavelength and therefore, frequency increases.
Calculation:
Let λ be the wavelength of the source S as measured by the observer when S is at position x₁ and λ’ be the wavelength of the source observed by the observer when S moves to position x₂.

Then the change in wavelength is ∆λ = λ – λ’ = v_st, where t is the time taken by the source to travel between x₁ and x₂ Therefore,
λ’ = λ – v_st … (1)
But t = \(\frac { λ }{ v }\) … (2)
On substituting equations (2) in equation (1), we get.
λ’ = λ(1 – \(\frac{v_{s}}{v}\))
Since frequency is inversely proportional to wavelength, we have

Since, \(\frac{v_{s}}{v}\) << 1, by using the binomial expansion and retaining only first order in \(\frac{v_{s}}{v}\), we get
f ‘ = f(1 + \(\frac{v_{s}}{v}\)) … (4)

(b) Source moves away from the observer Since the velocity of the source is opposite in direction when compared to case (a), hence by changing the sign of the velocity of the source in the above case i.e., by substituting (v_s → – v ) in equation (1), we get
f ‘= \(\frac{f}{\left(1+\frac{v_{s}}{v}\right)}\) … (5)
Using binomial expansion again, we get
f ‘= f(1 – \(\frac{v_{s}}{v}\)) … (6)

(ii) Observer in motion and source at rest:
(a) Observer moves towards Source:

We can assume that the observer O moves towards the source S with velocity v_o. The source S is at rest and the velocity of sound waves (with respect to the medium) produced by the source is v.
From the Figure, It is observed that both v_o and v are in opposite direction. Then, their relative velocity is v_r = v + v_o. The wavelength of the sound wave is λ = \(\frac { v }{ f }\), which means the frequency observed by the observer O is f ‘ = \(\frac{v_{r}}{\lambda}\). Then

(b) Observer recedes away from the Source: If the observer O is moving away (receding away) from the source S, then velocity v₀ and v move in the same direction. Hence, their relative velocity is v_r = v – v₀. Hence, the frequency observed by the observer O is

(iii) Both are in motion:
(a) Source and observer approach each other:

Let v_s and v_o be the respective velocities of source and observer approaching each other as shown in Figure. In order to calculate the apparent frequency observed by the observer, let us have a dummy (behaving as observer or source) in between the source and observer. Since the dummy is at rest, the dummy (observer) observes the apparent frequency due to approaching source as given in equation f ‘ =\(\frac{f}{\left(1-\frac{v_{s}}{v}\right)}\)
f_d = \(\frac{f}{\left(1-\frac{v_{s}}{v}\right)}\) … (1)
The true observer approaches the dummy from the other side at that instant of time. Since the source (true source) comes in a direction opposite to the true observer, the dummy (source) is treated as a stationary source for the true observer at that instant. Hence, apparent frequency when the true observer approaches the stationary source (dummy source), f’ = f(1 + \(\frac{v_{0}}{v}\)).

Since this is true for any arbitrary time, therefore, comparing equation (1) and equation (2), we get

(b) Source and observer recede from each other:

It is noticed that the velocity of the source and the observer each point in opposite directions with respect to the case in (a) and hence, we substitute (v_s → – v_s) and (v₀ → – v₀) in equation (3), and therefore, the apparent frequency observed by the observer when the source and observer recede from each other is f’ = \(\left(\frac{v-v_{0}}{v+v_{s}}\right)\)f

(c) Source chases the observer:

Only the observer’s velocity is oppositely directed when compared to case (a). Therefore, substituting (v₀ → – v₀) in equation (3), we get f’ = \(\left(\frac{v-v_{0}}{v-v_{s}}\right)\)f

(d) Observer chases the source:

Only the source velocity is oppositely directed when compared to case (a). Therefore, substituting (v_s → – v_s) in equation (3), we get f’ = \(\left(\frac{v+v_{0}}{v+v_{s}}\right)\)f

IV. Numerical Problems:

Question 1.
The speed of a wave in a certain medium is 900 m/s. If 3000 waves pass over a certain point of the medium in 2 minutes, then compute its wavelength?
Answer:
Given:

Question 2.
Consider a mixture of 2 mol of helium and 4 mol of oxygen. Compute the speed of sound in this gas mixture at 300 K.
Answer:
Number of molecules of helium = 2
Number of molecules of oxygen = 4
When helium and oxygen are mixed, hence the molecular weight of the mixture of gases is given by

In addition, helium is monoatomic,
\(\mathrm{C}_{v_{2}}\) = \(\frac { 2R }{ 2 }\)
Oxygen is diatomic \(\mathrm{C}_{v_{1}}\) = \(\frac { 5R }{ 2 }\)

Ratio of specific heat capacitors of a mixture of gases is

According to Laplace, the speed of sound in a gas is

∴ The speed of sound = 400.9 m/s

Question 3.
A ship in a sea sends SONAR waves straight down into the seawater from the bottom of the ship. The signal reflects from the deep bottom bedrock and returns to the ship after 3.5 s. After the ship moves to 100 km it sends another signal which returns back after 2 s. Calculate the depth of the sea in each case and also compute the difference in height between two cases.
Answer:
In the first case
time = 3.5s
Velocity sound in sea water = 1450 m/s
Distance 2d = v x t
= 1450 x 3.5 = 5,075 m
Depth of the sea d = \(\frac { 5075 }{ 2 }\) = 2537.5 m
In the second case,
time = 2s
Velocity of sound in water = 1450 m/s
Distance 2d = vt
= 1450 x 2
= 2900 m
Depth of the sea d = \(\frac { 2900 }{ 2 }\) = 1450
Difference ∆d = 2537.5 – 1450 = 1087.5
= 1087.5 m

Question 4.
A sound wave is transmitted into a tube as shown in the figure. The sound wave splits into two waves at point A which recombine at point B. Let R be the radius of the semi-circle which is varied until the first minimum. Calculate the radius of the semi-circle if the wavelength of the sound is 50.0 m.
Answer:

Path difference = πR – 2R
[Here AB = 2R; Semicircle path = πR]
Formula:
Path difference = (2n – 1)\(\frac { λ }{ 2 }\) (for minimum n – 1)

Question 5.
N tuning forks are arranged in order of increasing frequency and any two successive tuning forks give n beats per second when sounded together. If the last fork gives double the frequency of the first (called as octave), Show that the frequency of the first tuning fork is f = (N – 1)n.
Answer:
f,f + n,f+ 2n, … f + (m – 1)n
f + (N – 1)n = 2f
n = \(\frac { f }{ N-1 }\)
(or) f = n(N – 1)

Question 6.
Let the source propagate a sound wave whose intensity at a point (initially) be I. Suppose we consider a case when the amplitude of the sound wave is doubled and the frequency is reduced to one-fourth. Calculate now the new intensity of sound at the same point?
Answer:
Given:

Question 7.
Consider two organ pipes of the same length in which one organ pipe is closed and another organ pipe is open. If the fundamental frequency of closed pipe is 250 Hz. Calculate the fundamental frequency of the open pipe.
Answer:

Formula:

Question 8.
Police in a siren car moving with a velocity of 20 ms^-1 chases a thief who is moving in a car with a velocity v₀ms^-1. The police car sounds at frequency 300 Hz, and both of them move towards a stationary siren of frequency 400 Hz. Calculate the speed at which the thief is moving.
Answer:
Velocity of sound v = 330 m/s
Velocity of a police siren car v_s = 20 m/s
Frequency of a police siren car f = 300 Hz
Let the velocity of the thief be v m/s
The frequency of police siren heard by a thief is
f₁ = \(\left(\frac{330-v}{330-20}\right)\) x 300
= \(\left(\frac{330-v}{310}\right)\) x 300 Hz
Frequency of stationary siren = 400 Hz
Frequency of stationaiy siren heard by a thief
f₂ = \(\left(\frac{330+v}{330}\right)\) x 400
If there are no beats then

Question 9.
Consider the following function,
(a) y = x² + 2 α tx
(b) y = (x + vt)²
which among the above function can be characterized as a wave?
Answer:
Given:
Formula:
For the function to be a wave function \(\frac { (dy/dx) }{ (dy/dt) }\) should be a constant.
For function (a):

Hence, function
(a) does not describe a wave.
(b) satisfies wave function.

V. Conceptual Questions:

Question 1.
Why is it that transverse waves cannot be produced in a gas? Can the transverse waves be produced in solids and liquids?
Answer:
They travel in the form of crests and troughs and so involve a change in shape. They can be produced in a medium that has elasticity in shape. As gas has no elasticity of shape, hence transverse waves cannot be produced in a gas. Transverse waves can be produced in solids anion the surface of liquids.

Question 2.
Why is the roar of our national animal different from the sound of a mosquito?
Answer:
The pitch of the sound of our national animal lion is higher than that of mosquitoes. In addition, the frequency of sound waves generated by our national animal is more than the frequency of sound waves generated by mosquitoes.

Question 3.
A sound source and listener are both stationary and a strong wind is blowing. Is there a Doppler effect?
Answer:
When both source and listener are stationary, there is no relative motion between the source and the observer. Hence there is no Doppler effect.

Question 4.
In an empty room, why is it that a tone sounds louder than in the room having things like furniture, etc.
Answer:
When a room has furniture reverberation time can be suitably decreased since furniture has a large absorption coefficient of sound. So a tone sounds with lesser amplitude and intensity. Whereas in an empty room, reverberation time will be more than a room having things like furniture.

Question 5.
How do animals sense the impending danger of hurricanes?
Answer:
Hurricane produces a shock wave which has a speed greater than the speed of sound. It travels with a supersonic sound that can be easily sensed by animals using the Doppler effect. The multiple reflections of sound can be easily sensed by animals.

Question 6.
Is it possible to realize whether a vessel kept under the tap is about to fill with water?
Answer:
Yes. The frequency of a note generated by an air column is inversely proportional to its length. Consequently, as the length of the air column decreases, the frequency increases, i.e., the note becomes more shrill. In our case, when a vessel kept under the top is about to fill with water, as the water level rises, the length of the air column in the vessel goes on decreasing and the emitted sound becomes more and more shrill. Hence it is realised.

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Computer Science Guide Pdf Chapter 17 Computer Ethics and Cyber Security Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Computer Science Solutions Chapter 17 Computer Ethics and Cyber Security

11th Computer Science Guide Computer Ethics and Cyber Security Text Book Questions and Answers

Part -I

Choose The Correct Answer

Question 1.
Which of the following deals with procedures, practices and values?
a) piracy
b) programs
c) virus
d) computer ethics
Answer:
d) computer ethics

Question 2.
Commercial programs made available to the public illegally are known as
a) freeware
b) warez
c) free software
d) software
Answer:
b) warez

Question 3.
Which one of the following are self-repeating and do npt require a computer program to attach themselves?
a) viruses
b) worms
c) spyware
d) Trojans
Answer:
b) worms

Question 4.
Which one of the following tracks a user visits a website?
a) spyware
b) cookies
c) worms
d) Trojans
Answer:
b) cookies

Question 5.
Which of the following is not a malicious program on computer systems?
a) worms
d) Trojans
c) spyware
d) cookies
Answer:
d) cookies

Question 6.
A computer network security that monitors and controls incoming and outgoing traffic is
a) Cookies
b) Virus
c) Firewall
d) worms
Answer:
c) Firewall

Question 7.
The process of Converting cipher text to plain text is called
a) Encryption
b) Decryption
c) key
d) proxy server
Answer:
b) Decryption

Question 8.
e-commerce means
a) electronic commerce
b) electronic data exchange
c) electric data exchange
d) electronic commercialization.
Answer:
a) electronic commerce

Question 9.
Distributing unwanted e-mail to others is called
a) scam
b) spam
c) fraud
d) spoofing
Answer:
b) spam

Question 10.
Legal recognition for transactions are carried out by
a) Electronic Data Interchange
b) Electronic Data Exchange
c) Electronic Data Transfer
d) Electrical Data Interchange
Answer:
a) Electronic Data Interchange

Part – II

Very Short Answers

Question 1.
What is harvesting?
Answer:
A person or program collects login and password information from a legitimate user to illegally gain access to others account(s).

Question 2.
What are Warez?
Answer:
Commercial programs that are made available to the public illegally are often called warez.

Question 3.
Write a short note on cracking.
Answer:
Cracking is where someone edits a program source so that the code can be exploited or modified. “Cracking” means trying to get into computer systems in order to steal, corrupt, or illegitimately view data.

Question 4.
Write two types of cyber attacks.
Answer:
The following are cyber attacks:

• Virus
• Worms
• Spyware
• Ransomware

Question 5.
What is a Cookie?
Answer:
A cookie (also called HTTP cookie, web cookie, Internet cookie, browser cookie, or simply cookie) is a small piece of data sent from a website and stored on the user’s computer memory (Hard drive) by the user’s web browser while the user is browsing the internet.

Part – III

Short Answers

Question 1.
What is the role of firewalls?
Answer:
Role of firewalls:

• A firewall is a computer network security based system that monitors and controls incoming and outgoing network traffic based on predefined security rules.
• A firewall commonly establishes a block between a trusted internal computer network and entrusted computer outside the network.

Question 2.
Write about encryption and decryption.
Answer:
Encryption and decryption are processes that ensure confidentiality that only authorized persons can access the information. Encryption is the process of translating plain text data (plaintext) into random and mangled data (called ciphertext). Decryption is the reverse process of converting the ciphertext back to plaintext. Encryption and decryption are done by cryptography. In cryptography, a key is a piece of information (parameter) that determines the functional output of a cryptographic algorithm.

Question 3.
Explain symmetric key encryption.
Answer:
SYMMETRIC KEY ENCRYPTION:
Symmetric encryption is a technique to use the same key for both encryption and decryption.

The main disadvantage of symmetric key encryption is that all authorized persons involved, have to exchange the key used to encrypt the data before they can decrypt it. If anybody intercepts the key information, they may read all messages.
The following Figure depicts the working of symmetric key encryption.

Question 4.
What are the guidelines to be followed by any computer user?
Answer:
Generally, the following guidelines should be observed by computer users:

1. Honesty: Users should be truthful while using the internet.
2. Confidentiality: Users should not share any important information with unauthorized people.
3. Respect: Each user should respect the privacy of other users.
4. Professionalism: Each user should maintain professional conduct.
5. Obey The Law: Users should strictly obey the cyber law in computer usage.
6. Responsibility: Each user should take ownership and responsibility for their actions.

Question 5.
What are ethical issues? Name some of them.
Answer:
An Ethical issue is a problem or issue that requires a person or organization to choose between alternatives that must be evaluated as right (ethical) or wrong (unethical). These issues must be addressed and resolved to have a positive influence in society.

Some of the common ethical issues are listed below:

• Cyber crime
• Software Piracy
• Unauthorized Access
• Hacking
• Use of computers to commit fraud
• Sabotage in the form of viruses
• Making false claims using computers

Part IV

Explain in Detail

Question 1.
What are the various crimes happening using computers?
Answer:
Cyber Crime:
Cyber crime is an intellectual, white-collar crime. Those who commit such crimes generally manipulate the computer system in an intelligent manner. For example – illegal money transfer via the internet.

Examples of some Computer crimes and their functions are listed below in the following Table :

Crime	Function
Crime Function	Hacking, threats, and blackmailing towards a business or a person.
Cyber stalking	Harassing online.
Malware	Malicious programs can perform a variety of functions including stealing, encrypting or deleting sensitive data, altering or hijacking core computing functions, and monitoring user’s computer activity without their permission.
Denial of service attack	Overloading a system with fake requests so that it cannot serve normal legitimate requests.
Fraud	Manipulating data, for example changing the banking records to transfer money to an unauthorized account.
Harvesting	A person or program collects login and password information from a legitimate user to illegally gain access to others’ account(s).
Identity theft	It is a crime where the criminals impersonate individuals, usually for financial gain.
Intellectual property theft	Stealing practical or conceptual information developed by another person or company.
Salami slicing	Stealing tiny amounts of money from each transaction.
Scam	Tricking people into believing something that is not true.
Spam	Distribute unwanted e-mail to a large number of internet users.
Spoofing	It is a malicious practice in which communication is sent from an unknown source disguised as a source known to the receiver.

Question 2.
What is piracy? Mention the types of piracy? How can it be prevented?
Answer:
Software Piracy:
Software Piracy is about the copyright violation of software created originally by an individual or an institution. It includes stealing codes/programs and other information illegally and creating duplicate copies by unauthorized means and utilizing this data either for one’s own benefit or for commercial profit.

In simple words, Software Piracy is “unauthorized copying of software*’. The following Figure shows a diagrammatical representation of software piracy.

Types Of Piracy:

Shareware: An entirely different approach to software piracy is called shareware, which acknowledges the futility of trying to stop people from copying software and instead relies on people’s honesty.

Warez: Commercial programs that are made available to the public illegally are often called warez.

Prevention Method:

• Illegal copying and distribution of commercial software should not be practiced.
• Shareware publishers encourage users to give copies of programs to friends and colleagues but ask everyone who uses that program regularly to pay a registration fee to the program’s author directly.

Question 3.
Write the different types of cyber attacks.
Answer:
Types Of Cyber Attacks:
Malware is a type of software designed through which criminals gain illegal access to software and cause damage. Various types of cyber-attacks and their functions are given in the following Table.

No.	‘Cyber Attack	Function
1.	Virus	A virus is a small piece of computer code that can repeat itself and spreads from one computer to another by attaching itself to another computer file. One of the most common viruses is Trojan. Trojan A Trojan virus is a program that appears to perform one function (for example, virus removal) but actually performs malicious activity when executed.
2.	Worms	Worms are self-repeating and do not require a computer program to attach themselves. Worms continually look for vulnerabilities and report back to the author of the worm when weaknesses are discovered.
3.	Spyware	Spyware can be installed on the computer automatically when the attachments are open, by clicking on links or by downloading infected software.
4.	Ransomware	Ransomware is a type of malicious program that demands payment after launching a cyber-attack on a computer system. This type of malware has become increasingly popular among criminals and costs the organization millions each year.

11th Computer Science Guide Computer Ethics and Cyber Security Additional Questions and Answers

Part I

Choose The Correct Answer

Question 1.
A moral code that is evaluated as right is ………………..
(a) piracy
(b) viruses
(c) cracking
(d) ethics
Answer:
(d) ethics

Question 2.
Information Technology is widespread through ________
a) Computers
b) Mobile phones
c) Internet
d) All the above
Answer:
d) All the above

Question 3.
Stealing data from a computer system without knowledge or permission is called ………………..
(a) warez
(b) hacking
(c) cracking
(d) phishing
Answer:
(b) hacking

Question 4.
A(n) ________ is a crime which involves computer and network.
a) Cyber-crime
b) Ethics
c) Cyber-law
d) None of these
Answer:
a) Cyber-crime

Question 5.
……………….. is the intermediary between the end-users and a web browser.
(a) Firewall
(b) Proxy server
(c) Cookies
(d) Warez
Answer:
(b) Proxy server

Question 6.
________ is a cybercrime.
a) Phishing
b) Hacking
c) Identity thefts
d) All the above
Answer:
d) All the above

Question 7.
________ is a cybercrime.
a) Pharming
b) Piracy
c) Online financial transaction
d) All the above
Answer:
d) All the above

Question 8.
Ethics means________
a) What is wrong
b) What is Right
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 9.
________ is a set of moral principles that rule the behavior of individuals who use computers,
a) Ethics
b) Cyber-Crime
c) Virus
d) None of these
Answer:
a) Ethics

Question 10.
An individual gains knowledge to follow the right behavior, using morals that are also known as________
a) Ethics
c) Phishing
c) Hacking
d) None of these
Answer:
a) Ethics

Question 11.
________ refer to the generally accepted standards of right and wrong in the society,
a) Piracy
b) Morals
c) Virus
d) None of these
Answer:
b) Morals

Question 12.
________ is a cyber world standard.
a) Do not use pirated software
b) Do not hack
c) Do not steal others’ passwords
d) All the above
Answer:
b) Do not hack

Question 13.
________ is a guidelines of computer ethics.
a) Honesty
b) Confidentiality
c) Respect
d) All the above
Answer:
d) All the above

Question 14.
________ is a guidelines of computer ethics.
a) Professionalism
b) Obey the law
c) Responsibility
d) All the above
Answer:
d) All the above

Question 15.
Identify the correct statement from the following.
a) Ethics is a set of moral principles that govern the behavior of an individual in a society.
b) Computer ethics is set of moral principles that regulate the use of computers by users.
c) An Ethical issue is a problem or issue that requires a person or organization to choose between alternatives that must be evaluated as right or wrong.
d) All the above
Answer:
d) All the above

Question 16.
Identify the correct statement from the following related to ethics.
a) Users should be truthful while using the internet.
b) Users should not share any important information with unauthorized people.
c) Each user should respect the privacy of other users.
d) All the above
Answer:
d) All the above

Question 17.
Identify the correct statement from the following related to ethics.
a) Each user should maintain a professional conduct.
b) Users should strictly obey the cyber law in computer usage.
c) Each user should take ownership and responsibility for their actions
d) All the above
Answer:
d) All the above

Question 18.
Cybercrime is a(n) ________ crime.
a) Intellectual
b) White-collar
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 19.
Harassing through online is called ________
a) Cyber Stalking
b) Cyber Harassment
c) Cyber torture
d) None of these
Answer:
a) Cyber Stalking

Question 20.
________ are malicious programs that can perform a variety of functions on user’s computer activity without their permission.
a) Cyber Stalking
b) Malware
c) Antivirus
d) None of these
Answer:
b) Malware

Question 21.
Malicious programs that can perform a variety of functions including ________ on user’s Computer activity without their permission.
a) Encrypting or Deleting sensitive data
b) Stealing
c) Hijacking core computing functions
d) All the above
Answer:
d) All the above

Question 22.
Overloading a system with fake requests so that it cannot serve normal legitimate requests is called________
a) Cyber Stalking
b) Malware
c) Denial of service attack
d) None of these
Answer:
c) Denial of service attack

Question 23.
Manipulating data like changing the banking records to transfer money to an unauthorized account is called ________
a) Cyber Stalking
b) Malware
c) Denial of service attack
d) Fraud
Answer:
d) Fraud

Question 24.
________ means a person or program collects login and password information from a legitimate user to illegally gain access to others accounts.
a) Harvesting
b) Malware
c) Denial of service attack
d) Fraud
Answer:
a) Harvesting

Question 25.
________ is a crime where the criminals impersonate individuals, usually for financial gain.
a) Harvesting
b) Identity theft
c) Denial of service attack
d) Fraud
Answer:
b) Identity theft

Question 26.
________ means stealing practical or conceptual information developed by another person or company.
a) Harvesting
b) Identity theft
c) Intellectual property theft
d) Fraud
Answer:
c) Intellectual property theft

Question 27.
________ meant tricking people into believing something that is not true.
a) Harvesting
b) Scam
c) Intellectual property theft
d) Fraud
Answer:
b) Scam

Question 28.
Stealing tiny amounts of money from each transaction means ________
a) Salami slicing
b) Scam
c) Intellectual property theft
d) Fraud
Answer:
a) Salami slicing

Question 29.
Distribute unwanted e-mail to a large number of internet is termed as ________
a) Salami slicing
b) Scam
c) Intellectual property theft
d) Spam
Answer:
d) Spam

Question 30.
________ is a malicious practice in which communication is send from unknown source disguised as a source known to the receiver.
a) Salami slicing
b) Scam
c) Spoofing
d) Spam
Answer:
c) Spoofing

Question 31.
Software________ is about the copyright violation of software created originally by an individual or an institution.
a) Piracy
b) Fraud
c) Theft
d) None of these
Answer:
a) Piracy

Question 32.
________ includes stealing of codes / programs and other information illegally and creating duplicate copies by unauthorized means and utilizing this data either for one’s own benefit or for commercial profit.
a) Piracy
b) Scam
c) Salami slicing
d) None of these
Answer:
a) Piracy

Question 33.
To prevent unauthorized access ________ is used.
a) Firewalls/ Intrusion Detection Systems
b) Virus and Content Scanners
c) Patches and Hotfixes
d) All the above
Answer:
d) All the above

Question 34.
IDS means.________
a) Intrusion Detection Systems
b) Intrusion Defective Systems
c) Intrusion Direction Systems
d) Intrusion Detach Systems
Answer:
a) Intrusion Detection Systems

Question 35.
________ is intruding into a computer system to steal personal data without the owner’s permission or knowledge.
a) Piracy
b) Hacking
c) IDS
d) None of these
Answer:
b) Hacking

Question 36.
Steal a password is________
a) Piracy
b) Hacking
c) IDS
d) None of these
Answer:
b) Hacking

Question 37.
________ is where someone edits a program source so that the code can be exploited or modified.
a) Piracy
b) Hacking
c) Cracking
d) None of these
Answer:
c) Cracking

Question 38.
A cracker is called as a ________
a) Black hat
b) Dark side hacker
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 39.
Cracking means trying to get into computer systems in order to________ data.
a) Steal
b) Corrupt
c) Illegitimately view
d) All the above
Answer:
d) All the above

Question 40.
A ________ is someone who breaks into someone else’s computer system, often on a network, bypassing passwords or licenses in computer programs.
a) Cracker
b) Programmer
c) Server
d) None of these
Answer:
a) Cracker

Question 41.
Password cracking can be performed by________
a) Using an automated program
b) Can be manually realized
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 42.
IRC means ________
a) International Relay Chat
b) Internet Relay Chat
c) Internal Relay Chat
d) Internet Ready Chat
Answer:
b) Internet Relay Chat

Question 43.
The method that uses social engineering crackers is ________ guessing.
a) Password
b) Username
c) Website name
d) URL
Answer:
a) Password

Question 44.
Identify the correct statement from the following related with cracking.
a) It is a method of getting passwords and information using human weakness.
b) Crackers find your personal information from some persona! data/facts and try to guess a password.
c) Crackers may send official e-mail requesting some sensitive information. It may look like a legitimate e-mail from bank or other official institution.
d) All the above
Answer:
d) All the above

Question 45.
________ is a collection of various technologies, processes and measures that reduces the risk of cyber attacks.
a) Cyber Security
b) Cyber Crime
c) Cyber Gateway
d) None of these
Answer:
a) Cyber Security

Question 46.
________ protects organizations and individuals from computer based threats.
a) Cyber Security
b) Cyber Crime
c) Cyber Gateway
d) None of these
Answer:
a) Cyber Security

Question 47.
________ is a type of software designed through which the criminals gain iliegal access to software and cause damage.
a) Malware
b) Piracy
c) Cracking
d) None of these
Answer:
a) Malware

Question 48.
A ________ is a small piece of computer code that can repeat itself and spreads from one computer to another by attaching itself to another computer file.
a) Virus
b) Piracy
c) Cracking
d) None of these
Answer:
a) Virus

Question 49.
________ is the most common virus.
a) Trojan
b) Melisa
c) Sasser
d) Code Red
Answer:
a) Trojan

Question 50.
A ________ is a program that appears to perform one function but actually performs malicious activity when executed.
a) Cracking
b) Trojan virus
c) Piracy
d) None of these
Answer:
b) Trojan virus

Question 51.
________ can be installed on the computer automatically when the attachments are open, by clicking on links or by downloading infected software.
a) Spyware
b) Worms
c) Ransomware
d) None of these
Answer:
a) Spyware

Question 52.
________ is a type of malicious program that demands payment after launching a cyber-attack on a computer system.
a) Spyware
b) Worms
c) Ransomware
d) None of these
Answer:
c) Ransomware

Question 53.
________ type of malware has become increasingly popular among criminals and costs the organizations millions each year.
a) Spyware
b) Worms
c) Ransomware
d) None of these
Answer:
c) Ransomware

Question 54.
________ is an example of social engineering.
a) Phishing
b) Pharming
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 55.
Phishing is a type of computer crime used to attack, steal user data, including ________
a) Login name
b) Password
c) Credit card numbers
d) All the above
Answer:
d) All the above

Question 56.
________ occurs when an attacker targets a victim into opening an e-maiior an instant text message.
a) Phishing
b) Pharming
c) Both A and B
d) None of these
Answer:
a) Phishing

Question 57.
________ is a scamming practice in which malicious code is installed on a personal computer or server, misdirecting users to fraudulent web sites without their knowledge or permission.
a) Phishing
b) Pharming
c) Both A and B
d) None of these
Answer:
b) Pharming

Question 58.
Pharming has been called________
a) Phishing without a trap
b) Phishing with a trap
c) Illegal access
d) None of these
Answer:
a) Phishing without a trap

Question 59.
________ is a cyber-attack intended to redirect a website’s traffic to a fake site.
a) Phishing
b) Pharming
c) Trojan
d) None of these
Answer:
b) Pharming

Question 60.
MITM stands for ________
a) Man In The Middle
b) Malware In The Middle
c) Move In The Middle
d) Must In The Middle
Answer:
a) Man In The Middle

Question 61.
________ is an attack where the attacker secretly relays and possibly alters the communication between two parties who believe they are directly communicating With each other.
a) Cyber
b) Man-in-the-middle attack
c) Cracking
d) None of these
Answer:
b) Man-in-the-middle attack

Question 62.
MITM is also called as________
a) Janus attack
b) Junk attack
c) Genious attack
d) None of these
Answer:
a) Janus attack

Question 63.
A ________ is a small piece of data sent from a website and stored on the user’s computer memory (Hard drive) by the user’s web browser while the user is browsing internet,
a) Cookie
b) MITM
c) Cracking
d) Piracy .
Answer:
a) Cookie

Question 64.
A ________ cookie is also called as cookie.
a) HTTP or Web
b) Internet
c) Browser
d) All the above
Answer:
d) All the above

Question 65.
________ can be used to remember arbitrary pieces of information that the user previously entered into form fields such as names, addresses, passwords, and credit card numbers.
a) Cookie
b) MITM
c) Cracking
d) Piracy
Answer:
a) Cookie

Question 66.
An anonymous user is called as________
a) Hacker
b) Malware
c) Cracker
d) None of these
Answer:
a) Hacker

Question 67.
Who can access the cookie information and misuse it?
a) Hacker
b) Service provider
c) Cracker
d) None of these
Answer:
a) Hacker

Question 68.
Web sites typically use cookies for the ________ reason.
a) To collect demographic information about who has visited the Web site.
b) Sites often use this information to track how often visitors come to the site and how long they remain on the site.
c) It helps to personalize the user’s experience on the Web site.
d) All the above
Answer:
d) All the above

Question 69.
________ can help to store personal information about users so that when a user subsequently returns to the site.
a) Cookie
b) MITM
c) Cracking
d) Piracy
Answer:
a) Cookie

Question 70.
________ do not act maliciously on computer system.
a) Virus
b) MITM
c) Cracking
d) Cookie
Answer:
d) Cookie

Question 71.
________ are merely text files that can be deleted at any time.
a) Cookies
b) MITM
c) Cracking
d) Virus
Answer:
a) Cookies

Question 72.
________ cannot be used to spread viruses and they cannot access our hard drive.
a) MITM
b) Cookies
c) Cracking
d) Virus
Answer:
b) Cookies

Question 73.
A ________ commonly establishes a block between a trusted internal computer network and entrusted computer outside the network.
a) Firewall
b) Cookie
c) Hacking
d) None of these
Answer:
a) Firewall

Question 74.
Firewall category is ________
a) Network-based
b) Host-based
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 75.
________ firewalls are positioned on the gateway computers of LANs [Local Area Network], WANs [Wide Area Network] and intranets.
a) Network-based
b) Host-based
c) Either A or B
d) None of these
Answer:
a) Network-based

Question 76.
________ firewalls are positioned on the network node itself.
a) Network-based
b) Host-based
c) Either A or B
d) None of these
Answer:
b) Host-based

Question 77.
The ________ firewall may be a service as a part of the operating system or an agent application such as endpoint security or protection.
a) Network-based
b) Host-based
c) Either A or B
d) None of these
Answer:
b) Host-based

Question 78.
A ________ acts as an intermediary between the end-users and a web server.
a) Proxy server
b) System software
c) Node
d) None of these
Answer:
a) Proxy server

Question 79.
________ typically keep the frequently visited site addresses in its cache which leads to improved response time.
a) Proxy servers
b) System software
c) Node
d) None of these
Answer:
a) Proxy servers

Question 80.
________ is a process that ensures confidentiality that only authorized persons can access the information.
a) Encryption
b) Decryption
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 81.
________ is the process of translating the plain text data (plaintext) into random and mangled data.
a) Encryption
b) Decryption
c) Sampling
d) None of these
Answer:
a) Encryption

Question 82.
The encrypted text is called________
a) Cybertext
b) Cipher-text
c) Secured text
d) None of these
Answer:
b) Cipher-text

Question 83.
________ is the process of converting the cipher¬text back to plaintext.
a) Encryption
b) Decryption
c) Warping
d) None of these
Answer:
b) Decryption

Question 84.
________ is done by cryptography.
a) Encryption
b) Decryption
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 85.
In cryptography, a ________ is a piece of information that determines the functional output of a cryptographic algorithm.
a) Key
b) Parameter
c) Input
d) Output
Answer:
a) Key

Question 86.
Encryption has been used by ________ to facilitate secret communication.
a) Militaries
b) Governments
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 87.
________ now commonly used in protecting information within many kinds of civilian systems.
a) Encryption
b) Sampling
c) Warping
d) None of these
Answer:
a) Encryption

Question 88.
________ is used to protect data in communication system.
a) Encryption
b) Sampling
c) Warping
d) None of these
Answer:
a) Encryption

Question 89.
Encryption used in ________
a) Data being transferred via networks
b) Mobile telephones
c) Wireless microphones
d) All the above
Answer:
d) All the above

Question 90.
Encryption used in________
a) Wireless intercom systems
b) Bluetooth devices
c) Bank automatic teller machines
d) All the above
Answer:
d) All the above

Question 91.
Data should be ________ when transmitted across networks in order to protect against the network traffic by unauthorized users.
a) Encrypted
b) Translated
c) Converted
d) None of these
Answer:
a) Encrypted

Question 92.
There are________ types of encryption schemes.
a) three
b) four
c) two
d) five
Answer:
c) two

Question 93.
________ is a encryption scheme.
a) Symmetric Key encryption
b) Public Key encryption
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 94.
encryption is a technique to use the same key for both encryption and decryption.
a) Symmetric Key
b) Public Key
c) Either A and B
d) None of these
Answer:
a) Symmetric Key

Question 95.
In________ encryption all authorized persons involved, have to exchange the key used to encrypt the data before they can decrypt it.
a) Symmetric Key
b) Public Key
c) Either A and B
d) None of these
Answer:
a) Symmetric Key

Question 96.
________ encryption is also called Asymmetric encryption
a) Symmetric Key
b) Public Key
c) Both A and B
d) None of these
Answer:
b) Public Key

Question 97.
________ uses the concept of a key-value pair, a different key is used for the encryption and decryption process.
a) Symmetric Key encryption
b) Public Key encryption
c) Both A and B
d) None of these
Answer:
b) Public Key encryption

Question 98.
________ key is used in public key encryption.
a) Private
b) Public
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 99.
The ________ key is kept secret by the owner.
a) Private
b) Public
c) Both A and B
d) None of these
Answer:
a) Private

Question 100.
The ________ key is either shared amongst authorized recipients.
a) Private
b) Public
c) Both A and B
d) None of these
Answer:
b) Public

Question 101.
The data encrypted with the recipient’s ________ key can only be decrypted with the
corresponding key.
a) Public, Private
b) Private, Public
c) Public, Protected
d) None of these
Answer:
a) Public, Private

Question 102.
A digital certificate in a client-server model of communication is one of the example of________
a) Asymmetric Encryption
b) Symmetric
c) Either A or B
d) None of these
Answer:
a) Asymmetric Encryption

Question 103.
A________ is a package of information that identifies a user and a server.
a) Signature
b) Signal
c) Certificate
d) None of these
Answer:
c) Certificate

Question 104.
A certificate contains information such as________
a) An organization’s name
b) The organization that issued the certificate
c) The users’ email address and country and user’s public key
d) All the above
Answer:
d) All the above

Question 105.
Digital signatures are can provide ________ .
a) Assurances of evidence to origin
b) Identity and status of an electronic document, transaction or message
c) Acknowledging informed by the signer
d) All the above
Answer:
d) All the above

Question 106.
________ law is used to prevent cybercrime.
a) Cyber Law or Cyber Space Law
b) Information Technology Law
c) Internet Law
d) Either A or B or C
Answer:
d) Either A or B or C

Question 107.
In India Cyberlaw and IT Act 2000, modified in ________ are being articulated to prevent computer crimes.
a) 2018
b) 2008
c) 1998
d) None of these
Answer:
b) 2008

Question 108.
EDI stands for ________
a) Electronic Data Interchange
b) Electronic Document Interchange
c) Electronic Data Information
d) Electrical Data Interchange
Answer:
a) Electronic Data Interchange

Question 109.
________ is a term that encapsulates the legal issues related to using of the Internet.
a) Cyberlaw
b) Internet law
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 110.
________ of cybercrime remains unsolved.
a) 75%
b) 50%
c) 25%
d) 10%
Answer:
c) 25%

Question 111.
To protect the information follow________
a) Complex password setting can make your surfing secured.
b) When the internet is not in use, disconnect it.
c) Do NOT open spam mail or emails that have an unfamiliar sender.
d) All the above
Answer:
d) All the above

Question 112.
Identify the correct statement from the following:
a) Information security is the immune system in the body of business.
b) Awareness is the key to security.
c) When using anti-virus software, keep it up-to-date.
d) All the above
Answer:
d) All the above

Part II

Very Short Answers

Question 1.
What is hacking?
Answer:
Hacking is intruding into a computer system to steal personal data without the owner’s permission or knowledge (like to steal a password). It is also gaining unauthorized access to a computer system, and altering its contents.

Question 2.
What is cyber-crime?
Answer:
A cyber-crime is a crime which involves computer and network. This is becoming a growing threat to society and is caused by criminals or irresponsible actions of individuals who are exploiting the widespread use of the Internet.

Question 3.
Mention any 2 reasons as to why the websites use cookies?
Answer:

1. To collect demographic information about who has visited the Web site.
2. It helps to personalize the user’s experience on the Website.

Question 4.
What are the types of Cybercrime?
Answer:
It is depicted in the following diagram:

Question 5.
Define software piracy.
Answer:
Software Piracy is about the copyright violation of software created originally by an individual or an institution. It includes stealing codes/programs and other information illegally and creating duplicate copies by unauthorized means and utilizing this data either for one’s own benefit or for commercial profit.

Question 6.
What are the standards in the cyber-world?
Answer:
In the cyber-world, there are certain standards such as:

• Do not use pirated software.
• Do not use unauthorized user accounts.
• Do not steal others’ passwords.
• Do not hack.

Question 7.
What are the core issues in computer ethics?
Answer:
The core issues in computer ethics are based on the scenarios arising from the use of the internets such as privacy, the publication of copyrighted content, unauthorized distribution of digital content, and user interaction with websites, software, and related services.

Question 8.
What are the changes in society due to the internet?
Answer:

• With the help of the internet, the world has now become a global village.
• The Internet has been proven to be a boon to individuals as well as various organizations and businesses.
• e-Commerce is becoming very popular among businesses as it helps them to reach a wide range of customers faster than any other means;

Question 9.
What are the roles of computer ethics?
Answer:
Computer ethiŒ deals with the proœdures, values, and practices that govern the process of consuming computer technology and its related disciplines without damaging or violating the moral values and beliefs of any individual, organization, or entity.

Question 10.
What is the difference between ethics and computer ethics?
Answer:

• Ethics is a set of moral principles that govern the behavior of an individual in a society.
• Computer ethics is set of moral principles that regulate the use of computers by users.

Question 11.
What is cybercrime? Give an example.
Answer:
Cyber Crime
Cybercrime is an intellectual, white-collar crime. Those who commit such crimes generally manipulate the computer system in an intelligent manner.
For example – illegal money transfer via the internet.

Question 12.
How to prevent unauthorized access?
Answer:
To prevent unauthorized access, Firewalls, Intrusion Detection Systems (IDS), Virus and Content Scanners, Patches and Hotfixes are used.

Question 13.
What is social engineering? Give an example.
Answer:
Social engineering
A misuse of an individual’s weakness, achieved by making them to click malicious links, or by physically accessing the computer through tricks. Phishing and pharming.

Question 14.
What are Cookies?
Answer:
A cookie is a small piece of data sent from a website and stored on the user’s computer memory (Hard drive) by the user’s web browser while the user is browsing the internet.

Question 15.
What are the types of encryption?
Answer:
There are two types of encryption schemes as listed below:

• Symmetric Key encryption
• Public Key encryption

Question 16.
What is a certificate?
Answer:
A certificate is a package of information that identifies a user and a server. It contains information such as an organization’s name, the organization that issued the certificate, the users’ email address and country, and the user’s public key.

Question 17.
What is a digital certificate?
Answer:

• A digital certificate in a client-server model of communication.
• It is one of the examples of Asymmetric Encryption.

Question 18.
What is a digital signature?
Answer:
Digital signatures are based on asymmetric cryptography and can provide assurances of evidence to origin, identity, and status of an electronic document, transaction, or message, as well as acknowledging informed by the signer.

Question 19.
Write a note on Cyberlaw or Internet law.
Answer:
Cyberlaw or Internet law is a term that encapsulates the legal issues related to using the Internet.

Question 20.
Write about IT Act 2000.
Answer:
IT Act 2000 is an act to provide legal recognition for transactions carried out by means of Electronic Data Interchange (EDI) and other means of electronic communication.

Part III

Short Answers 3 Marks

Question 1.
What are the guidelines of ethics?
Answer:
GUIDELINES OF ETHICS:
Generally, the following guidelines should be observed by computer users:

• Honesty: Users should be truthful while using the internet.
• Confidentiality: Users should not share any important information with unauthorized people.
• Respect: Each user should respect the privacy of other users.
• Professionalism: Each user should maintain professional conduct.
• Obey The Law: Users should strictly obey the cyber law in computer usage.
• Responsibility: Each user should take ownership and responsibility for their actions

Question 2.
Write a short note on ethics.
Answer:
Ethics means “What is Wrong and What is Right”. It is a set of moral principles that rule the behavior of individuals who use computers. An individual gains knowledge to follow the right behavior, using morals that are also known as ethics. Morals refer to the generally accepted standards of right and wrong in society. Similarly, in the cyber world, there are certain standards such as

1. Do not use pirated software.
2. Do not use unauthorized user accounts.
3. Do not steal others’ passwords.
4. Do not hack.

Question 3.
Write a note on unauthorized access.
Answer:
UNAUTHORIZED ACCESS:
Unauthorized access is when someone gains access to a website, program, server, service, or another system by breaking into a legitimate user account.

For example, if someone tries guessing a password or user name for an account that was not theirs until they gained access, it is considered unauthorized access.

Question 4.
What are cyber-attack and cybersecurity?
Answer:

• Cyber attacks are launched primarily for causing significant damage to a computer system or for stealing important information from an individual or from an organization.
• Cybersecurity is a collection of various technologies, processes, and measures that reduces the risk of cyber-attacks and protects organizations and individuals from computer-based threats.

Question 5.
What is phishing? Explain with a suitable diagram.
Answer:
Phishing:
Phishing is a type of computer crime used to attack, steal user data, including login name, password and credit card numbers. It occurs when an attacker targets a victim into opening an e-mailer an instant text message.

The attacker uses phishing to distribute malicious links or attachments that can perform a variety of functions including the extraction of sensitive login credentials from victims.

Diagrammatic representation of Phishing

Question 6.
What is Pharming? Explain with suitable diagram.
Answer:
Pharming:
Pharming is a scamming practice in which malicious code is installed on a personal computer or server, misdirecting users to fraudulent web sites without their knowledge or permission.

Pharming has been called “phishing without a trap”. It is another way hackers attempt to manipulate users on the Internet. It is a cyberattack intended to redirect a website’s traffic to a fake site.

Diagrammatic representation of Pharming :

Question 7.
What do you mean by Man In The Middle attack or Janus attack? Illustrate in a diagram.
Answer:
Man In The Middle (MITM) :
A man-in-the-middle attack (MITM; also Janus attack) is an attack where the attacker secretly relays and possibly alters the communication between two parties who believe they are directly communicating with each other.

Example:
Suppose Alice wishes to communicate with Bob. Meanwhile, Mallory wishes to intercept the conversation to overhear and optionally to deliver a false message to Bob.

An illustration of the man-in-the-middle attack :

Question 5.
Write down the points to be noted to be safe from cybercrime.
Answer:
To protect the information the following points to be noted:

1. A complex password setting can make your surfing secured.
2. When the internet is not in use, disconnect it.
3. Do NOT open spam mail or emails that have an unfamiliar sender.
4. When using anti-virus software, keep it up to date.

Question 9.
Explain the working of the Proxy Server.
Answer:
A proxy server acts as an intermediary between the end-users and a web server. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resources available from a different server.

The proxy server examines the request, checks authenticity, and grants the request based on that. Proxy servers typically keep the frequently visited site addresses in their cache which leads to improved response time.

Question 10.
How to prevent cybercrime?
Answer:
To protect the information the following points to be noted:

• A complex password setting can make your surfing secured.
• When the internet is not in use, disconnect it.
• Do NOT open spam mail or emails that have an unfamiliar sender.
• When using anti-virus software, keep it up-to-date.

Part IV

Explain in Detail

Question 1.
List the computer crimes and their functions.
Answer:

Crime	Function
Crime Function	Hacking, threats, and blackmailing towards a business or a person.
Cyberstalking	Harassing online.
Malware	Malicious programs can perform a variety of functions including stealing, encrypting, or deleting sensitive data, altering or hijacking core computing functions, and monitoring user’s computer activity without their permission.
Denial of service attack	Overloading a system with fake requests so that it cannot serve normal legitimate requests.
Fraud	Manipulating data, for example changing the banking records to transfer money to an unauthorized account.
Harvesting	A person or program collects login and password information from a legitimate user to illegally gain access to others’ account(s).
Identity theft	It is a crime where the criminals impersonate individuals, usually for financial gain.
Intellectual property theft	Stealing practical or conceptual information developed by another person or company.
Salami slicing	Stealing tiny amounts of money from each transaction.
Scam	Tricking people into believing something that is not true.
Spam	Distribute unwanted e-mail to a large number of internet users.
Spoofing	It is a malicious practice in which communication is sent from an unknown source disguised as a source known to the receiver.

Question 2.
Explain Hacking in detail.
Answer:
HACKING:
Hacking is intruding into a computer system to steal personal data without the owner’s permission or knowledge (like to steal a password). It is also gaining unauthorized access to a computer system, and altering its contents. It may be done in pursuit of criminal activity or it may be a hobby.
Diagrammatic representation of Hacking

Question 3.
Write short notes on:

1. Spam
2. Fraud
3. Cyberstalking
4. Spoofing
5. Virus
6. Worms

Answer:

1. Spam: Distribute unwanted email to a large number of internet users.
2. Fraud: Manipulating data, for example changing the banking records to transfer money to an unauthorized account.
3. Cyberstalking: Harassing through online.
4. Spoofing: It is a malicious practice in which communication is sent from an unknown source disguised as a source known to the receiver.
5. Virus: A virus is a small piece of computer code that can repeat itself and spreads from one computer to another by attaching itself to another computer file. One of the most common viruses is Trojan.
6. Worms: Worms are self – repeating and do not require a computer program to attach themselves. Worms continually look for vulnerabilities and report back to the author of the worm when weaknesses are discovered.

Question 4.
Explain the working of the Firewall server. Firewall Server:
Answer:
A firewall is a computer network security-based system that monitors and controls the incoming and outgoing network traffic based on predefined security rules. A firewall commonly establishes a block between a trusted internal computer network and entrusted computer outside the network.

They are generally categorized as network-based or host-based.

Network-based firewalls are positioned on the gateway computers of LANs [local area Network], WANs [Wide Area Network], and intranets.

Host-based firewalls are positioned on the network node itself. The host-based firewall may be a service as a part of the operating system or an agent application such as endpoint security or protection.

Question 5.
Explain public key encryption.
Answer:
PUBLIC KEY ENCRYPTION:
Public key encryption is also called asymmetric encryption. It uses the concept of a key-value pair, a different key is used for the encryption and decryption process. One of the keys is typically known as the private key and the other is known as the public key.

The private key is kept secret by the owner and the public key is either shared amongst authorized re.dQle.ats. cvr made, available to the public at large.

The data encrypted with the recipient’s public key can only be decrypted with the corresponding private key.

Question 6.
What is a digital signature? Explain the function of the digital signature with a suitable diagram.
Answer:
Digital Signature:
Digital signatures are based on asymmetric cryptography and can provide assurances of evidence to origin, identity, and status of an electronic document, transaction, or message, as well as acknowledging informed by the signer.

To create a digital signature, signing software (email) creates a one-way hash of the electronic data to be signed. The user’s private key encrypts the hash, returning a value that is unique to the hashed data.

The encrypted hash, along with other information such as the hashing algorithm, forms the digital signature. Any change in the data, even to a single bit, results in a different hash value. This attribute enables others to validate the integrity of the data by using the signer’s public key to decrypt the hash.

If the decrypted hash matches a second computed hash of the same data, it proves that the data hasn’t changed since it was signed.

If the two hashes don’t match, the data has either been tampered with in some way (indicating a failure of integrity) or the signature was created with a private key that doesn’t correspond to the public key presented by the signer (indicating a failure of authentication).

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Computer Science Guide Pdf Chapter 18 Tamil Computing Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Computer Science Solutions Chapter 18 Tamil Computing

11th Computer Science Guide Tamil Computing Text Book Questions and Answers

Very Short Answers

Question 1.
List of the search engines supporting Tamil.
Answer:
Google and Bing provide searching facilities in Tamil, which means you can search everything through Tamil. A Google search engine gives you an inbuilt Tamil virtual keyboard.

Question 2.
What are the keyboard layouts used in Android?
Answer:
Sellinam and Ponmadal are familiar Tamil keyboard layouts that work on the Android operating system in Smart phone using phonetics.

Question 3.
Write a short note about Tamil Programming Language.
Answer:
Based on the Python programming language, the first Tamil programming language “Ezhil” (எழில்) is designed. With the help of this programming language, you can write simple programs in Tamil.

Question 4.
What TSCII?
Answer:
TSCII (Tamil Script Code for Information Interchange) is the first coding system to handle our Tamil language in an analysis of an encoding scheme that is easily handled in electronic devices, including non-English computers.
This encoding scheme was registered in the IANA (Internet Assigned Numbers Authority) unit of ICANN.

Question 5.
Write a short note on Tamil Virtual Academy
Answer:
With the objectives of spreading Tamil to the entire world through the internet, Tamil Virtual University was established on 17th February 2001 by the Govt, of Tamil Nadu. Now, this organisation is functioning with the name “Tamil Virtual Academy”. This organisation offers different courses regarding the Tamil language, culture, heritage, etc., from kindergarten to under graduation level.

11th Computer Science Guide Tamil Computing Additional Questions and Answers

Part I

I. Choose The Correct Answer 1 Mark 

Question 1.
Human civilization developed with the innovation of computer in the ……………
(a) 11th century
(b) 13th century
(c) 16th century
(d) 20th century
Answer:
(d) 20th century

Question 2.
_______ internet users consider local language digital content to be more reliable than English.
a) 74%
b) 68%
c) 42%
d) 28%
Answer:
b) 68%

Question 3.
Getting government services through the internet is known as ……………
(a) e-library
(b) e-governance
(c) Tamil programming language
(d) Tamil translation applications
Answer:
(b) e-governance

Question 4.
From 2021 onwards, _______of people in India will access the internet using Tamil.
a) 74%
b) 68%
c) 42%
d) 28%
Answer:
a) 74%

Question 5.
The _______are used to search any information from cyberspace.
a) Search Engines
b) Browsers
c) Cookies
d) None of these
Answer:
a) Search Engines

Question 6.
In the top ten search engines, _______takes first place.
a) Google
b) Bing
c) Yahoo
d) None of these
Answer:
a) Google

Question 7.
In the top ten search engines,_______takes second place.
a) Google
b) Bing
c) Yahoo
d) None of these
Answer:
b) Bing

Question 8.
In the top ten search engines, _______takes third place.
a) Google
b) Bing
c) Yahoo
d) None of these
Answer:
c) Yahoo

Question 9.
_______search engine provides searching facilities in Tamil.
a) Google
b) Bing
c) Yahoo
d) Google and Bing
Answer:
d) Google and Bing

Question 10.
A _______search engine gives you an inbuilt Tamil virtual keyboard.
a) Google
b) Bing
c) Yahoo
d) Google and Bing
Answer:
a) Google

Question 11.
Getting Government services through the internet is known as_______
a) e-Services
b) e-Governance
c) Web Governance
d) None of these
Answer:
b) e-Governance

Question 12.
Outside India, the Government of _______provides all their services through the official website in Tamil.
a) Srilanka
b) Canada
c) Nepal
d) None of these
Answer:
a) Srilanka

Question 13.
_______are portal or website of collection of e-books.
a) E-Libraries
b) E-Learning
c) E-Content
d) None of these
Answer:
a) E-Libraries

Question 14.
_______ is a familiar Tamil keyboard interface software that is used for Tamil typing which works on Tamil Unicode, using phonetics.
a) NHM Writer
b) E-Kalappai
c) Lippikar
d) All the above
Answer:
d) All the above

Question 15.
_______is a familiar Tamil keyboard layout that works on the Android operating system in Smartphone using phonetics.
a) Sellinam
b) Ponmadal
c) Sellinam and Ponmadal
d) None of these
Answer:
c) Sellinam and Ponmadal

Question 16.
_______ office automation software provides a complete Tamil interface facility.
a) Microsoft Office
b) Open Office
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 17.
_______is office automation software working exclusively for Tamil.
a) Azhagi Unicode Editor
b) Ponmozhi & Menthamiz
c) Kamban and Vani
d) All the above
Answer:
d) All the above

Question 18.
_______ is a Tamil translation application having more than 30000 Tamil words equivalent to English words.
a) Thamizpori
b) Sellinam
c) Ponmadal
d) None of these
Answer:
a) Thamizpori

Question 19.
The first Tamil programming language is _______
a) Thamizpori
b) Ezhil
c) Kamban
d) None of these
Answer:
b) Ezhil

Question 20.
With the help of _______ programming language, you can write simple programs in Tamil.
a) Thamizpori
b) Ezhil
c) Kamban
d) None of these
Answer:
b) Ezhil

Question 21.
Expand TSCII
a) Telugu Script Code for Information Interchange
b) Total Script Code for Information Interchange
c) Tamil Script Code for Information Interchange
d) Technical Script Code for Information Interchange
Answer:
c) Tamil Script Code for Information Interchange

Question 22.
Computers are handle data and information as a _______ system.
a) Binary
b) Decimal
c) Octal
d) Hexadecimal
Answer:
a) Binary

Question 23.
The ASCII encoding system is applicable only for handling _______ language.
a) English
b) Hindi
c) French
d) Tamil
Answer:
a) English

Question 24.
_______is the first coding System to handle our Tamil language in an analysis of an encoding scheme that is easily handled in electronic devices, including non-English computers.
a) ASCII
b) TSCII
c) EBCDIC
d) None of these
Answer:
b) TSCII

Question 25.
IANA means _______
a) Internet Assigned Numbers Authority
b) Internet Assigned Names Authority
c) Internet Access Numbers Authority
d) Intranet Assigned Numbers Authority
Answer:
a) Internet Assigned Numbers Authority

Question 26.
Expand ISCII
a) International Script Code for Information Interchange
b) Internet Script Code for Information Interchange
c) Indian Script Code for Information Interchange
d) Instant Script Code for Information Interchange
Answer:
c) Indian Script Code for Information Interchange

Question 27.
_______encoding schemes specially designed for Indian languages including Tamil.
a) ASCII
b) EBCDIC
c) BCD
d) ISCII
Answer:
d) ISCI

Question 28.
_______ is an encoding system, designed to handle various world languages, including Tamil.
a) ASCII
b) EBCDIC
c) UNICODE
d) ISCII
Answer:
c) UNICODE

Question 29.
Unicode first version 1.0.0 was introduced on _______
a) October 1991
b) October 2001
c) October 1993
d) October 1999
Answer:
a) October 1991

Question 30.
A(n) _______is needed to access electronic systems such as computer and smartphone.
a) Browser
b) Operating system
c) Search Engine
d) None of these
Answer:
b) Operating system

Question 31.
Identify the correct statement from the following.
a) An operating system should be easy to work and its environment should be in an understandable form.
b) Windows Tamil Environment interface shows all windows elements such as Taskbar, desktop elements, names of icons, commands in Tamil.
c) Among the various encoding scheme, Unicode is suitable to handle Tamil.
d) All the above
Answer:
d) All the above

Question 32.
Tamil Virtual University was established on _____ by the Govt, of Tamilnadu.
a) 17th February 1991
b) 17th February 2011
c) 17th February 2001
d) 27th February 2001
Answer:
c) 17th February 2001

Question 33.
_______organisation offers different courses regarding Tamil language, Culture, heritage, etc., from kindergarten to under graduation level.
a) Tamil Virtual Institute
b) Tamil Virtual Academy
c) Tamil Virtual Association
d) Tamil Virtual Organisation
Answer:
b) Tamil Virtual Academy

Question 34.
_______ is an open and voluntary initiative to collect and publish free electronic editions of ancient Tamil literary classics.
a) Project Madurai
b) Project Tamilnadu
c) Project Madras
d) Project Nellai
Answer:
a) Project Madurai

Question 35.
In 1998, Project Madurai released in Tamil script form as per _______ encoding.
a) ASCII
b) TSCII
c) BCD
d) None of these
Answer:
b) TSCII

Very Short Answers (2 Marks)

Question 1.
What is e-governance?
Answer:
Getting Government services through the internet is known as e-Governance. Govt, of Tamil Nadu, has been giving its services through the Internet. One can communicate with Govt, of Tamil Nadu from any comer of the state. One can get important announcements, government orders, and government welfare schemes from the web portal of Govt. of. Tamil Nadu.

Question 2.
Which search engine provides an inbuilt Tamil virtual keyboard.
Answer:
The Google search engine gives you an inbuilt Tamil virtual keyboard.

Question 3.
Explain Tamil translation applications.
Answer:
Thamizpori (தமிஸ்ப்பூரி) is a Tamil translation application having more than 30000 Tamil words equivalent to English words. Using this application, we can translate small English sentences into Tamil. Google also gives an online translation facility, using this online facility we can translate from Tamil to any other language and vice versa.

Question 4.
Write about the Tamil translation application.
Answer:
Thamizpori (தமிஸ்ப்பூரி) is a Tamil translation application having more than 30000 Tamil words equivalent to English words? Using this application, we can translate small English sentences into Tamil. Google also gives an online translation facility, using this online facility we can translate from Tamil to any other language vice versa.

Question 5.
Explain ISCII.
Answer:
Indian Script Code for Information Interchange (ISCII ), is one of the encoding schemes specially designed for Indian languages including Tamil. It was unified with Unicode.

Short Answers

Question 1.
What is Unicode?
Answer:
Unicode is an encoding system, designed to handle various world languages, including Tamil. Its first version 1.0.0 was introduced in October 1991. While the introduction of this scheme can be able to handle nearly 23 languages including Tamil. Among the various encoding scheme, Unicode is suitable to handle Tamil.

Question 2.
List the website address of popular e-Libraries.
Answer:

Tamil e-Library		Website address
Tamilnadu School Education and Teacher Education Training Textbooks and Resource Books		http://www.textbooksonline.tn.nic.in/
Tamil Virtual Academy		http://www.tamilvu.org/library/libindex.htm
Connemara Public Library		http://connemarapublic librarychennai.com/ Veettukku_oru_noolagam /index.html
Tamil Digital Library		http://tamildigitallibrary.in/
Chennai Library		http://www.chennailibrary.com/
Thamizhagam		http: //www. thamizhagam.net/parithi/ parithi.html

Question 3.
Write a short note on Tamil on the internet.
Answer:
Internet is the best information technological device, through which we get know everything from the Internet. In 2017 a study conducted by KPMG a Singapore-based organization along with google reported that Tamil topped the list, among the most widely used languages in India where 42% are using the Internet in Tamil. Moreover, in 2021 onwards, 74% of people in India will access the internet using Tamil and it will be in the top usage of the Internet in India.

Question 4.
Write a note on Unicode.
Answer:
Unicode is an encoding system, designed to handle various world languages, including Tamil. Its first version 1.0.0 was introduced in October 1991. While the introduction of this scheme can be able to handle nearly 23 languages including Tamil. Among the various encoding scheme, Unicode is suitable to handle Tamil.

Question 5.
Write a note on the Tamil operating system.
Answer:
An operating system should be easy to work and its environment should be in an understandable form. Thus, all operating systems used in computers and smartphones offered an environment in Tamil.
Windows Tamil Environment interface should be downloading and install from the internet. It shows all windows elements such as Taskbar, desktop elements, names of icons, commands in Tamil.

Explain in Detail (5 Marks)

Question 1.
Write about Tamil Office Automation Applications.
Answer:
Famous Office automation software like Microsoft Office, Open Office, etc., provides a complete Tamil interface facility. These softwares are downloadable and installed on your computer.

After installation, our office automation software environment will completely change to Tamil. Menu bars, names of icons, dialog boxes will be shown in Tamil. Moreover, you can save files with Tamil names and create folders with Tamil names.

Apart from that Tamil Libra Office, Tamil Open Office, Azhagi Unicode Editor, Ponmozhi, Menthamiz, Kamban, Vani are office automation software working exclusively for Tamil. These applications are designed to work completely in Tamil.

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Computer Science Guide Pdf Chapter 2 Number Systems Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Computer Science Solutions Chapter 2 Number Systems

11th Computer Science Guide Number Systems Text Book Questions and Answers

Part – I

I. Choose The Correct Answer :

Question 1.
Which is a basic electronic circuit which operates on one or more signals?
a) Boolean algebra
b) Gate
c) Fundamental gates
d) Derived gates
Answer:
b) Gate

Question 2.
Which gate is called as the logical inverter?
a) AND
b) OR
c) NOT
d) XNOR
Answer:
c) NOT

Question 3.
A + A = ?
a) A
b) O
c) 1
d) A
Answer:
a) A

Question 4.
NOR is a combination of ?
a) NOT(OR)
b) NOT(AND)
c) NOT(NOT)
d) NOT(NOR)
Answer:
a) NOT(OR)

Question 5.
NAND is called as _______ Gate
a) Fundamental Gate
b) Derived Gate
c) Logical Gate
d) Electronic gate
Answer:
b) Derived Gate

Part II

Short Answers:

Question 1.
What is Boolean Algebra?
Answer:
Boolean algebra is a mathematical discipline that is used for designing digital circuits in a digital computer. It describes the relationship between inputs and outputs of a digital circuit.

Question 2.
Write a short note on NAND Gate.
Answer:
The NAND gate operates an AND gate followed by a NOT gate. It acts in the manner of the logical operation “AND” followed by an inversion. The output is “false” if both inputs are “true” otherwise, the output is “true”. In other words, the output of the NAND gate is 0 if and only if both the inputs are 1, otherwise the output is 1.
The logical symbol of the NAND gate is

The truth table for NAND gate is

Input		Output
A	‘ B	C
0	0	1
0	1	1
1	0	1
1	1	0

Question 3.
Draw the truth table for the XOR gate.
Answer:
The truth table for XOR gate is

In put		Output
A	‘ B	C
0	0	0
0	1	1
1	0	1
1	1	0

Question 4.
Write the associative laws?
Answer:
A + (B + C) = (A + B) + C
A.(B.C) = (A.B).C

Question 5.
What are derived gates?
Answer:
The logic gates which are derived from the fundamental gates are called derived gates. Ex. NAND, NOR, XOR and XNOR are derived gates.

Part – III

Explain In Brief

Question 1.
Write the truth table of fundamental gates.
Answer:
The fundamental logic gates are AND, OR, and NOT gates.
The truth table for AND Gate is

Input		Output
A	B	C
0	0	0
0	1	0
1	0	0
1	1	1

The truth table for OR gate is

Input		Output
A	B	C
0	0	0
0	1	1
1	0	1
1	1	1

The truth table for NOT gate is

Input	Output
A	C
1	0
0	1

Question 2.
Write a short note on the XNOR gate.
Answer:
The XNOR (exclusive – NOR) gate is a combination XOR gate followed by an inverter. Its output is “true” if the inputs are the same, and “false” if the inputs are different. In simple words, the output is 1 if the input is the same, otherwise, the output is 0. The logic symbol of the XNOR gate is

The truth table for XNOR Gate is

Input		Output
A	B	C
0	0	1
0	1	0
1	0	0
1	1	1

Question 3.
Reason out why the NAND and NOR are called universal gates?
Answer:
NAND and NOR gates are called Universal gates because the fundamental logic gates can be realized through them.

Question 4.
Give the truth table of XOR gate.
Answer:
The truth table for XOR Gate is

Input		Output
A	B	C
0	0	0
0	1	1
1	0	1
1	1	0

Question 5.
Write the De Morgan’s law.
Answer:
De Morgan’s \(\overline{\mathrm{A}+\mathrm{B}}\) = \(\overline{\mathrm{A}}\) . \(\overline{\mathrm{B}}\)
(\(\overline{\mathrm{A}+\mathrm{B}}\)) = \(\overline{\mathrm{A}}\) + \(\overline{\mathrm{B}}\)

Part IV

Explain In Detail

Question 1.
Explain the fundamental gates with an expression and truth table.
Answer:
A gate is a basic electronic circuit which operates on one or more signals to produce an output signal. There are three fundamental gates namely AND, OR and NOT.

AND Gate
The AND gate can have two or more input signals and produce an output signal. The output is “true” only when both inputs are “true” otherwise, the output is “false”. In other words the output will be 1 if and only if both inputs are 1; otherwise, the output is 0.

The logical symbol of the AND gate is

The output of the AND gate is C = A . B or C = AB
The truth table for AND Gate is

Input		Output
A	B	C
0	0	0
0	1	0
1	0	0
1	1	1

OR Gate
The OR gate gets its name from its behaviour like the logical inclusive “OR”. The output is “true” if either or both of the inputs are “true”. If both inputs are “false” then the output is “false”. In other words, the output will be 1 if and only if one or both inputs are 1; otherwise, the output is 0.
The logical symbol of the OR gate is

The OR gate output is C = A OR B. We use the + sign to denote the OR function. Therefore, C = A + B.
The truth table for OR Gate is

Input		Output
A	B	C
0	0	0
0	1	1
1	0	1
1	1	1

NOT Gate
The NOT gate, called a logical inverter, has only one input. It reverses the logical state. In other words the output C is always the complement of the input.
The logical symbol of the NOT gate is

The boolean function of NOT gate is C = NOT A. In boolean algebra, the overbar stands for NOT operation. Therefore, \(C=\bar{A}\)
The truth table for NOT gate is

Input	Output
A	C
1	0
0	1

Question 2.
How AND and OR can be realized using NAND and NOR gate.
Answer:
NAND and NOR gates are called Universal gates because the fundamental logic gates can be realized through them.
NAND gates can be used to implement the fundamental logic gates NOT, AND, and OR.

NOR gates can also be used to implement NOT, OR and AND gates.

Question 3.
Explain the Derived gates with expression and truth table.
Answer:
The other logic gates like NAND, NOR, XOR, and XNOR are derived gates which are derived from the fundamental gates.

NOR Gate
The NOR gate circuit is an OR gate followed by an inverter. Its output is “true” if both inputs are “false” Otherwise, the output is “false”. In other words, the only way to get ‘1’ as output is to have both inputs ‘O’. Otherwise, the output is 0. The logic circuit of the NOR gate is

The logic symbol of NOR gate is

The output of the NOR gate is C = A + B
The truth table for NOR gate is

Input		Output
A	B	C
0	0	1
0	1	0
1	0	0
1	1	0

NAND Gate

The NAND gate operates an AND gate followed by a NOT gate. It acts in the manner of the logical operation “AND” followed by an inversion. The output is “false” if both inputs are “true” otherwise, the output is “true”. In other words, the output of the NAND gate is 0 if and only if both the inputs are 1, otherwise the output is 1. The logic circuit of the NAND gate is

The logical symbol of NAND gate is

The output of the NAND gate is \(C=\overline{A . B}\)
The truth table for NAND gate is

Input		Output
A	B	C
0	0	1
0	1	1
1	0	1
1	1	0

XOR Gate
The XOR (exclusive – OR) gate acts in the same way as the logical “either/or.” The output is “true” if either, but not both, of the inputs, are “true”. The output is “false” if both inputs are “false” or if both inputs are “true.” Another way of looking at this circuit is to observe that the output is 1 if the inputs are different, but 0 if the inputs are the same. The logic circuit of the XOR gate is

The logical symbol of XOR gate is

The output of the XOR gate is
\(\begin{aligned}
C &=A \oplus B \\
&=\bar{A} \cdot B+A \cdot \bar{B}
\end{aligned}\)

The truth table for XOR gate is

Input		Output
A	B	C
0	0	0
0	1	1
1	0	1
1	1	0

XNOR Gate
The XNOR (exclusive – NOR) gate is a combination XOR gate followed by an inverter. Its output is “true” if the inputs are the same, and “false” if the inputs are different. In simple words, the output is 1 if the input are the same, otherwise the output is 0. The logic circuit of XNOR gate is

The Logic Symbol is

In boolean algebra, \(\mathrm{A} \odot \mathrm{B}\) or “included dot” stands for the XNOR.
Therefore, C = \(\mathrm{A} \odot \mathrm{B}\)
The truth table for XNOR gate is

Input		Output
A	B	C
0	0	1
0	1	0
1	0	0
1	1	1

11th Computer Science Guide Number Systems Additional Questions and Answers

Part I

I. Choose The Correct Answer :

Question 1.
_______ is used for designing digital circuits in a digital computer.
a) Boolean algebra
b) Calculus
c) Iteration
d) None of these
Answer:
a) Boolean algebra

Question 2.
_______describes the relationship between inputs and outputs of a digital circuit.
a) Boolean algebra
b) Calculus
c) Iteration
d) None of these
Answer:
a) Boolean algebra

Question 3.
Who proposed the basic principles of boolean algebra?
a) George Boole
b) Charles Babbage
c) John Napier
d) Lady Ada Lovelace
Answer:
a) George Boole

Question 4.
The sentences which can be determined to be True or False are called _______ .
a) Logical Statement
b) Truth Functions
c) Either A or B
d) None of these
Answer:
a) Logical Statement

Question 5.
The results of a logical statement True or False are called _______
a) Truth Values
b) Constant
c) True value
d) None of these
Answer:
a) Truth Values

Question 6.
The truth values depicted by logical constant as_________ .
a) 1
b) 0
c) 1 and 0
d) None of these
Answer:
c) 1 and 0

Question 7.
The truth value depicted by logical constant 1 means _______
a) False
b) True
c) Either True or False
d) None of these
Answer:
b) True

Question 8.
The truth value depicted by logical constant 0 means _______
a) False
b) True
c) Either True or False
d) None of these
Answer:
a) False

Question 9.
The variable which can store truth values are called _______ variables.
a) Logical
b) Binary valued
c) Boolean
d) A OR B OR C
Answer:
a) Logical

Question 10.
Boolean algebra makes use of _______
a) variables
b) operations
c) Both A AND B
d) None of these
Answer:
c) Both A AND B

Question 11.
The basic logical operation is _______
a) AND
b) OR
c) NOT
d) All the above
Answer:
d) All the above

Question 12.
The basic logical operation AND is symbolically represented by _______.
a) dot (.)
b) plus ( + )
c) over bar / single apostrophe
d) None of these
Answer:
a) dot (.)

Question 13.
The basic logical operation OR is symbolically represented by _______.
a) dot (.)
b) plus ( + )
c) over bar / single apostrophe
d) None of these
Answer:
b) plus ( + )

Question 14.
The basic logical operation NOT is symbolically represented by
a) dot (.)
b) plus ( + )
c) over bar / single apostrophe
d) None of these
Answer:
c) over bar / single apostrophe

Question 15.
_______symbol is called as Logical Operator.
a) dot (.)
b) plus ( + )
c) over bar / single apostrophe
d) All the above
Answer:
d) All the above

Question 16.
A represents all the possible values of logical variables or statements along with all the possible results of a given combination of truth values.
a) Truth table
b) Log table
c) I/O Table
d) None of these
Answer:
a) Truth table

Question 17.
_______boolean operator is similar to multiplication in ordinary algebra.
a) AND
b) OR
c) NOT
d) All the above
Answer:
a) AND

Question 18.
The AND operator takes _______inputs.
a) only one
b) only two
c) two or more
d) None of these
Answer:
c) two or more

Question 19.
The _______operator output is true only if all the inputs are true.
a) AND
b) OR
c) NOT
d) All the above
Answer:
a) AND

Question 20.
The OR operator takes _______ inputs.
a) only one
b) only two
c) two or more
d) None of these
Answer:
c) two or more

Question 21.
The _______ operator output is true if at least one input is true.
a) AND
b) OR
c) NOT
d) All the above
Answer:
b) OR

Question 22.
The _______operator has one input and one output
a) AND
b) OR
c) NOT
d) All the above
Answer:
c) NOT

Question 23.
The ______operator inverts the input.
a) AND
b) OR
c) NOT
d) All the above
Answer:
c) NOT

Question 24.
Identify the true statements from the following.
a) The NOT operator input is either true or false and the output is always the opposite.
b) Boolean algebra is a mathematical discipline that is used for designing digital circuits.
c) The AND operator will give only one output
d) All the above
Answer:
d) All the above

Question 25.
The_________is the combination of NOT and AND.
a) NOR
b) NAND
c) XNOR
d) Bubbled AND
Answer:
b) NAND

Question 26.
The _________is generated by inverting the output of an OR operator.
a) NOR
b) NAND
c) XNOR
d) Bubbled AND
Answer:
b) NAND

Question 27.
The algebraic expression of the NAND function is:
a) \(Y=\overline{A . B}\)
b) \(Y=\overline{A+B}\)
c) \(Y=\overline{\bar{A} \cdot \bar{B}}\)
d) \(Y=\bar{A} \cdot \bar{B}\)
Answer:
a) \(Y=\overline{A . B}\)

Question 28.
The _________ is the combination of NOT and OR.
a) NOR
b) NAND
c) XNOR
d) Bubbled AND
Answer:
a) NOR

Question 29.
The ____________ is generated by inverting the output of an AND operator.
a) NOR
b) NAND
c) XNOR
d) Bubbled AND
Answer:
a) NOR

Question 30.
The algebraic expression of the NOR function is:
a) \(Y=\overline{A . B}\)
b) \(Y=\overline{A+B}\)
c) \(Y=\overline{\bar{A} \cdot \bar{B}}\)
d) \(Y=\bar{A}+\bar{B}\)
Answer:
b) \(Y=\overline{A+B}\)

Question 31.
_________ is a fundamental logic gate.
a) AND
b) NAND
c) NOT
d) Bubbled AND
Answer:
d) Bubbled AND

Question 32.
is a derived gate.
a) NOR
b) NAND
c) XNOR
d) All the above
Answer:
d) All the above

Question 33.
is not a derived gate.
a) BUBBLED AND
b) NAND
c) XNOR
d) NOT
Answer:
d) NOT

Question 34.
A . is a basic electronic circuit which operates on one or more signals to produce an output signal.
a) logic gate
c) boolean algebra
c) boolean gate
d) None of these
Answer:
a) logic gate

Question 35.
_________gate is called universal gate.
a) NAND
b) NOR
c) NAND and NOR
d) None of these
Answer:
c) NAND and NOR

Question 36.
The fundamental logic gates can be realized through _________gate.
a) NAND
b) NOR
c) NAND and NOR
d) None of these
Answer:
c) NAND and NOR

Question 37.
The _________ gate has only one input.
a) NAND
b) NOR
c) NOT
d) XNOR
Answer:
c) NOT

Question 38.
A bubbled AND gate produces the same output as a _________gate.
a) NAND
b) NOR
c) NOT
d) XNOR
Answer:
b) NOR

Question 39.
We can replace e.v H NOR gate by a _________gate.
a) NAND
b) NOR
c) Bubbled AND
d) Bubbled OR
Answer:
c) Bubbled AND

Question 40.
The output of NOR gate is _________if both inputs are “false”.
a) true
b) false
c) either true or false
d) None of these
Answer:
a) true

Question 41.
The output of the NAND gate is 0 if and only if both the inputs are _________
a) 0
b) 1
c) false
d) None of these
Answer:
b) 1

Question 42.
The truth tables of the bubbled OR gate and _________ gates are identical.
a) NAND
b) NOR
c) Bubbled AND
d) XOR
Answer:
a) NAND

Question 43.
We can replace each NAND gate by a _________gate.
a) NAND
b) NOR
c) Bubbled AND
d) Bubbled OR
Answer:
d) Bubbled OR

Question 44.
A+B represents _________ gate
a) XOR
b) NOR
c) NOT
d) XNOR
Answer:
a) XOR

Question 45.
In XOR gate, the output is _________ if the inputs are different.
a) 0
b) 1
c) 1 or 0
d) None of these
Answer:
b) 1

Question 46.
In XOR gate, the output is _________if the inputs are same.
a) 0
b) 1
c) 1 or 0
d) None of these
Answer:
a) 0

Question 47.
The _________gate is a combination XOR gate followed by an Inverter.
a) XOR
b) NOR
c) NOT
d) XNOR
Answer:
d) XNOR

Question 48.
A ® B represent _________gate.
a) XOR
b) NOR
c) NOT
d) XNOR
Answer:
d) XNOR

Question 49.
Identify the true statement from the following.
a) Using a combination of logic gates, complex operations can be performed.
b) Arrays of logic gates are found in digital integrated circuits.
c) In boolean algebra, © or “included dot” stands for the XNOR.
d) All the above
Answer:
d) All the above

Question 50.
AB + \(\overline{\mathbf{A}} \overline{\mathbf{B}}\) is the equation for gate.
a) XOR
b) NOR
c) NOT
d) XNOR
Answer:
d) XNOR

Question 51.
\(\bar{A} B+A B\) is the equation for _________gate.
a) XOR
b) NOR
c) NOT
d) XNOR
Answer:
a) XOR

Question 52.
The logical symbol of XOR gate is _________.

Answer:
a

Part II

Short Answers:

Question 1.
What are the logical operations?
Answer:
The basic logical operations are AND, OR, and NOT, which are symbolically represented by a dot ( . ), plus ( + ), and over bar / single apostrophe respectively. These symbols are also called “Logical Operators”.

Question 2.
What is Truth Table?
Answer:
A truth table represents all the possible values of logical variables or statements along with all the possible results of a given combination of truth values.

Question 3.
Write a note on NOT operator.
Answer:
The NOT operator has one input and one output. The input is either true or false, and the output is always the opposite, that is, the NOT operator inverts the input.
The truth table for a NOT operator where A is the input variable and Y is the output is shown below:

A	Y
0	1
1	0

The NOT operator is represented algebraically by the Boolean expression: Y = A.
The truth table for NAND gate is \(\mathbf{Y}=\overline{\mathbf{A}}\)

Question 4.
What are the universal gates? Why it is called so?
Answer:
NAND and NOR gates are called Universal gates because the fundamental logic gates can be realized through them.

Question 5.
What is logic gate? What are the fundamental logic gates?
Answer:
A gate is a basic electronic circuit which operates on one or more signals to produce an output signal.
There are three fundamental gates namely AND, OR, and NOT.

Question 6.
Write the commutative theorem of boolean algebra.
Answer:
i) A + B = B + A
ii) A . B = B . A.

Question 7.
Write the associative theorem of boolean algebra.
Answer:
i) A + (B + C) = (A + B) + C
ii) A . (B . C) = (A . B) . C.

Question 8.
Write the distributive theorem of boolean algebra.
Answer:
i) A . (B + C) = A . B + A . C
ii) A + (B . C) = (A + B) . (A + C).

Question 9.
Write the absorption theorem of Boolean algebra.
Answer:
i) A + (A . B) = A
ii) A . (A + B) = A.

Question 10.
Write the 3rd distributive theorem of Boolean algebra.
Answer:
A + A 1 B = A + B

Question 11.
Write the De Morgan’s theorems of Boolean algebra.
\(i) \overline{\mathrm{A}+\mathrm{B}}=\overline{\mathrm{A}} \cdot \overline{\mathrm{B}}
ii) \overline{\mathrm{A} \cdot \mathrm{B}}=\overline{\mathrm{A}}+\overline{\mathrm{B}}\)

Question 12.
Write the Null element theorem of Boolean algebra.
Answer:
i) A + 1 = 1
ii) A . 0 = 0

Question 13.
Write the Identity theorem of Boolean algebra.
Answer:
i) A + 0 = A
ii) A . 1 = A

Question 14.
Write the complement theorem of Boolean algebra.
Answer:
i) A + A = 1
ii) A . A = 0.

Part – III

Explain In Brief

Question 1.
Write note on AND operator.
Answer:
The AND operator is defined in Boolean algebra by the use of the dot (.) operator. It is similar to multiplication in ordinary algebra. The AND operator combines two or more input variables so that the output is true only if all the inputs are true. The truth table for a 2-input AND operator is shown as follows:

A	B	Y
0	0	0
0	1	0
.1	0	0
1	1	1

The above 2-input AND operation is expressed as:
Y = A . B.

Question 2.
Write note on OR operator.
Answer:
The plus sign is used to indicate the OR operator. The OR operator combines two or more input variables so that the output is true if at least one input is true. The truth table for a 2-input OR operator is shown as follows:

A	B	y
0	0	0
0	1	1
1	0	1
1	1	1

The above 2-input OR operation is expressed as Y = A + B.

Question 3.
Write a note on the NAND operator.
Answer:
The NAND is the combination of NOT and AND. The NAND is generated by inverting the output of an AND operator. The algebraic, expression of the NAND function is: Y = \(\overline{\mathrm{A}, \mathrm{B}}\)
The NAND function truth table is shown below:

A	B	y
0	0	1
0	1	1
1	0	1
1	1	0

A NAND B = NOT (A AND B).

Question 4.
Write a note on the NOR operator.
Answer:
The NOR is the combination of NOT and OR. The NOR is generated by inverting the output of an OR operator. The algebraic expression of the NOR function is: Y = \(\overline{A+B}\)
The NOR function truth table is shown below:

A	B	y
0	0	1
0	1	0
1	0	0
1	1	0

A NOR B = NOT (A OR B).

Question 5.
Explain AND gate with its symbols and truth table.
Answer:
The AND gate can have two or more input signals and produce an output signal. The output is “true” only when both inputs are “true” otherwise, the output is “false”. In other words, the output will be 1 if and only if both inputs are 1; otherwise, the output is 0.

The output of the AND gate is represented by a variable say C, where A and B are two and if input boolean variables. In boolean algebra, a variable can take either of the values ‘0’ or ‘1’. The logical symbol of the AND gate is

One way to symbolize the action of an AND gate is by writing the boolean function.
C = A AND B

In Boolean algebra, the multiplication sign stands for the AND operation. Therefore, the output of the AND gate is
C = A . B or simply C = AB

The truth table for AND Gate is

Input		Output
A	B	C
0	0	0
0	1	0
1	0	0
1	1	1

Question 6.
Explain OR gate with its symbols and truth table.
Answer:
The OR gate gets its name from its behaviour like the logical inclusive “OR”. The output is “true” if either or both of the inputs are “true”. If both inputs are “false” then the output is “false”. In other words, the output will be 1 if and only if one or both inputs are 1; otherwise, the output is 0. The logical symbol of the OR gate is

The OR gate output is C = A OR B
We use the + sign to denote the OR function.
Therefore, C = A + B
The truth table for OR gate is 

Input		Output
A	B	C
0	0	0
0	1	1
1	0	1
1	1	1

The boolean function of NOT gate is C = NOT A In boolean algebra, the overbar stands for NOT operation. Therefore, \(C=\bar{A}\)

Question 7.
Explain NOT gate with its symbols and truth table.
Answer:
The NOT gate, called a logical inverter, has only one input. It reverses the logical state. In other words, the output C is always the complement of the input. The logical symbol of the NOT gate is

The boolean function of NOT gate is C = NOT A
In boolean algebra, the overbar stands for NOT operation. Therefore, \(C=\bar{A}\)

The truth table for NOT gate is

Input	Output
A	C
1	0
0	1

Question 8.
Explain NOR gate with its symbols and truth table.
Answer:
The NOR gate circuit is an OR gate followed by an inverter. Its output is “true” if both inputs are “false” Otherwise, the output is “false”. In other words, the only way to get ‘1’ as output is to have both inputs ‘O’. Otherwise, the output is 0. The logic circuit of the NOR gate is

The Logic Symbol of NOR Gate is

The output of NOR gate is \(C=\overline{A+B}\)
The truth table for NOR gate is

Input		Output
A	‘ B	C
0	0	1
0	1	0
1	0	0
1	1	0

Question 9.
Explain Bubbled AND gate with its symbols and truth table.
Answer:
The Logic Circuit of Bubbled AND Gate

In the above circuit, inverters on the input lines of the AND gate gives the output as C = A.B.
The Logic symbol of Bubbled AND Gate is

The truth table of Bubbled AND Gate is

Input		Output
A	B	C
0	0	1
0	1	0
1	0	0
1	1	0

Part IV

Explain In Detail

Question 1.
Explain Bubbled OR gate with its symbols and truth table.
Answer:
The logic circuit of bubbled OR gate is

The output of this circuit can be written as \(C=\bar{A}+\bar{B}\)
The Logic symbol of Bubbled OR Gate is

The truth table for the bubbled OR is

Question 2.
Explain the XOR gate with its symbols and truth table.
Answer:
The XOR (exclusive – OR) gate acts in the same way as the logical “either/or.” The output is “true” if either, but not both, of the inputs, are “true”. The output is “false” if both inputs are “false” or if both inputs are “true.”
Another way of looking at this circuit is to observe that the output is 1 if the inputs are different, but 0 if the inputs are the same.
The Logic circuit of XOR Gate is

The output of the XOR gate is
\(C=A \oplus B=\bar{A} B+A B\)
The Logic symbol of XOR Gate is

The truth table for XOR gate is

Input		Output
A	‘ B	C
0	0	1
0	1	0
1	0	0
1	1	0

Question 3.
Explain the XNOR gate with its symbols and truth table.
Answer:
The XNOR (exclusive – NOR) gate is a combination XOR gate followed by an inverter. Its output is
true” if the inputs are the same, and “false” if the inputs are different. In simple words, the output is 1 if the input are the same, otherwise, the output is 0.
The logic circuit of the XNOR gate is

The output of the XNOR is NOT of XOR
\(C=(A \oplus B)^{\prime}=A B+\bar{A} \bar{B}\)
In boolean algebra, 0 or “included dot” stands for
the XNOR.
Therefore, C = \(\mathrm{A} \odot \mathrm{B}\)
The logical symbol is

The truth table for the XNOR gate is

Input		Output
A	‘ B	C
0	0	1
0	1	0
1	0	0
1	1	1

Question 4.
Write all the theorems of boolean algebra.
Answer:
Theorems of boolean algebra.
Identity
A + 0 = A
A • 1 = A

Complement
\(\begin{array}{l}
A+\bar{A}=1 \\
A \cdot \bar{A}=0
\end{array}\)

Commutative
A + B = B + A
A . B = B . A

Associative
A + (B + C) = (A + B) + C
A . (B . C) = (A; B) . C

Distributive
A-(B + C) = A- B + A- C
A + (B . C) = (A + B) . (A + C)

Null Element
A + 1 = 1
A . 0 = 0

Involution
\((\overline{\bar{A}})=A\)

Indempotence
A + A = A
A . A = A

Absorption
A + (A . B) = A
A . (A + B) = A

3rd Distributive
A + A.B = A + B

De Morgan’s
\(\begin{aligned}
\overline{A+B} &=\bar{A} \cdot \bar{B} \\
\overline{A . B} &=\bar{A}+\bar{B}
\end{aligned}\)

Question 5.
List all the logic gates with their symbols and truth tables.
Answer:
Logic Gates and their corresponding Truth Tables

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Chemistry Guide Pdf Chapter 2 Quantum Mechanical Model of Atom Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Chemistry Solutions Chapter 2 Quantum Mechanical Model of Atom

11th Chemistry Guide Quantum Mechanical Model of Atom Text Book Back Questions and Answers

Textual Questions:

I. Choose the best Answer:

Question 1.
Electronic configuration of species M²⁺ is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ and its atomic weight is 56. The number of neutrons in the nucleus of species M is
(a) 26
(b) 22
(c) 30
(d) 24
Answer:
(c) 30

Question 2.
The energy of light of wavelength 45nm is
(a) 6.65 × 10¹⁵ J
(b) 6.67 × 10¹¹ J
(c) 4.42 × 10^-18 J
(d) 4.42 × 10^-5 V
Answer:
(c) 4.42 × 10^-18 J

Question 3.
The energies E₁ and E₂ of two radiation are 25 eV and 50 eV respectively. The radiation between their wavelengths ie., λ₁ and λ₂ will be
(a) \(\frac{\lambda_{1}}{\lambda_{2}}\) = 1
(b) λ₁ = 2 λ₂
(c) λ₁ = \(\sqrt{225 \times 50}\) λ₂
(d) 2λ₁ = λ₂
Answer:
(b) λ₁ = 2 λ₂

Question 4.
Splitting of spectral lines in an electric field is called
(a) Zeeman effect
(b) shielding effect
(c) Compton effect
(d) stark effect
Answer:
(d) stark effect

Question 5.
Based on equation E = -2.178 × 10^-18 J(z²/n²), certain conclusions are written. Which of them is not correct?
(a) Equation can be used to calculate the change in energy when the electron changes orbit
(b) For n – 1 , the electron has a more negative energy then it does for n = 6 which means that the eiectron is more loosely bound in the smallest allowed orbit
(c) The negative sign in equation simply means that the energy of electron bound to the nucleus is lower than it would be if the electrons were at the infinite distance ffome nucleus.
(d) Larger the value of n, the larger is the orbit radius.
Answer:
(b) For n – 1 , the electron has a more negative energy then it does for n = 6 which means that the eiectron is more loosely bound in the smallest allowed orbit.

Question 6.
According to the Bohr Theory , which of the following transitions in the hydrogen atom will give rise to least energetic photon?
(a) n = 6 to n = 1
(b) n = 5 to n = 4
(c) n = 5 to n = 3
(d) n = 6 to n = 5
Answer:
(d) n = 6 to n = 5

Question 7.
Assertion:
The spectrum of He⁺ is expected to be similar to that of hydrogen
Reason: He⁺ is also one electron system.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true but reasons is not the correct explanation of assertion.
(c) If assertion is true but reason is false
(d) If both assertion and reason are false
Answer:
(a) If both assertion and reason are true and reason is the correct explanation of assertion.

Question 8.
Which of the following pairs of d-orbitals will have electron density along the axes?
(a) dz², dxz
(b) dxz, dyz
(c) dx², dx² – y²
(d) dxy, dx² – y²
Answer:
(c) dx², dx² – y²

Question 9.
Two electron occupying the same orbital are distinguished by
(a) Azimuthal quantum number
(b) Spin quantum number
(c) Magnetic quantum number
(d) Orbital quantum number
Answer:
(b) Spin quantum number

Question 10.
The electronic configuration of Eu (Atomic no, 63), Gd (Atomic no . 64), and Tb (Atomic no. 65) are
(a) [Xe] 4f⁶ 5d¹ 6s², [Xe] 4f⁷ 5d¹ 6s² and [Xe] 4f⁸ 5d¹ 6s²
(b) [Xe] 4f⁷ 6s², [Xe] 4f¹ 5d¹ 6s² and [Xe] 4f⁹ 6s²
(c) [Xe] 4f⁷ 6s², [Xe] 4f⁸ 6s² and [Xe] 4f⁸ 5d¹ 6s²
(d) [Xe] 4f⁶ 5d¹ 6s², [Xe] 4f¹ 5d¹ 6s² and [Xe] 4f⁹ 6s²
Answer:
(b) [Xe] 4f⁷ 6s², [Xe] 4f¹ 5d¹ 6s² and [Xe] 4f⁹ 6s²

Question 11.
The maximum number of electrons in a sub shell is given by the expression
(a) 2n²
(b) 2l + 1
(c) 4l + 2
(d) none of these
Answer:
(c) 4l + 2

Question 12.
For d-electrons, the orbit angular momentum is
(a) \(\frac{\sqrt{2} h}{2 \pi}\)

(b) \(\frac{\sqrt{2 h}}{2 \pi}\)

(c) \(\frac{\sqrt{2 \times 4} \mathrm{~h}}{2 \pi}\)

(d) \(\frac{\sqrt{6} \mathrm{~h}}{2 \pi}\)
Answer:
(d) \(\frac{\sqrt{6} \mathrm{~h}}{2 \pi}\)

Question 13.
What is the maximum number electrons that car be associated with following set of quantum numbers? n = 3, l = 1 and m = -1
(a) 4
(b) 6
(c) 2
(d) 10
Answer:
(c) 2

Question 14.
Assertion:
The number of radials and angular nodes for 3p orbital are I, 1 respectively.
Reason:
The number of radials and angular nodes depends only one the quantum number.
(a) Both assertion and reason are true and the reason is the correct explanation of the assertion
(b) Both assertion and reason are true but the reason is not the correct explanation of the assertion
(c) Assertion is true but the reason is false
(d) Both assertion and reason are false
Answer:
(c) Assertion is true but the reason is false

Question 15.
The total number of orbitals associated with the principal quantum number n = 3 is
(a) 9
(b) 8
(c) 5
(d) 7
Answer:
(a) 9

Question 16.
If n = 6, the sequence for filling electrons will be,
(a) ns → (n – 2)f → (n – 1)d → np
(b) ns → (n – 1 )d → (n – 2)f → np
(c) ns → {n – 2)f → np → (n – 1 )d
(d) none of these are correct
Answer:
(a) ns → (n – 2)f → (n – 1)d → np

Question 17.
Consider the following sets of quantum numbers:

Which of the following sets of quantum numbers is not possible?
(a) (i), (ii) and (iv)
(b) (ii), (iv) and (v)
(c) (i) and (iii)
(d) (ii), (iii) and (iv)
Answer:
(b) (ii), (iv) and (v)

Question 18.
How many electrons in an atom with atomic number 105 can have (n + l) = 8?
(a) 30
(b) 17
(c) 15
(d) unpredictable
Answer:
(b) 17

Question 19.
Electron density in the yz plane of 3d_{x² – y²} orbital is
(a) zero
(b) 0.50
(c) 0.75
(d) 0.90
Answer:
(a) zero

Question 20.
If uncertainty in position and momentum are equal, then minimum uncertainty in velocity is
(a) \(\frac{1}{m} \sqrt{\frac{h}{\pi}}\)

(b) \(\sqrt{\frac{\mathrm{h}}{\pi}}\)

(c) \(\frac{1}{2 m} \sqrt{\frac{h}{\pi}}\)

(d) \(\frac{\mathrm{h}}{4 \pi}\)
Answer:
(c) \(\frac{1}{2 m} \sqrt{\frac{h}{\pi}}\)

Question 21.
A macroscopic particle of mass 100 g and moving at a velocity of 100 cm s^-1 will have a de Broglie wavelength of
(a) 6.6 × 10^-29 cm
(b) 6.6 × 10^-30 cm
(c) 6.6 × 10^-31 cm
(d) 6.6 × 10^-32 cm
Answer:
(c) 6.6 × 10^-31 cm

Question 22.
The ratio of de Brogue wavelengths of a deuterium atom to that of an α – particle, when the velocity of the former is five times greater than that of later, is
(a) 4
(b) 0.2
(c) 2.5
(d) 0.4
Answer:
(d) 0.4

Question 23.
The energy of an electron in the 3rd orbit of a hydrogen atom is -E. The energy of an electron in the first orbit will be
(a)-3E
(b) -E/3
(c) -E/9
(d) -9E
Answer:
(d) -9E

Question 24.
Time independent Schnodinger wave equation is
(a) Hψ = Eψ
(b) ∆²ψ + 8π²m(E + V)ψ
(c) \(\frac{\partial^{2} \psi}{\partial x^{2}}+\frac{\partial^{2} \psi}{\partial y^{2}}+\frac{\partial^{2} \psi}{\partial z^{2}}+\frac{2 m}{h^{2}}(\mathrm{E}-\mathrm{V}) \psi=0\)
(d) all of these
Answer:
(a) Hψ = Eψ

Question 25.
Which of the following does not represent the mathematical expression for the Heisenberg uncertainty principle?
(a) ∆x . ∆p ≥ \(\frac{h}{4}\)
(b) ∆x . ∆v ≥ \(\frac{h}{4 \pi m}\)
(c) ∆E . ∆t ≥ \(\frac{h}{4 \pi}\)
(d) ∆E . ∆x ≥ \(\frac{h}{4 \pi}\)
Answer:
(d) ∆E . ∆x ≥ \(\frac{h}{4 \pi}\)

II. Write brief answers to the following questions:

Question 26.
Which quantum number reveals information about the shape, energy, orientation, and size of orbitals?
Answer:
Magnetic quantum numbers reveal information about the shape, energy, orientation, and size of orbitals.

Question 27.
How many orbitals are possible for n = 4?
Answer:
When n = 0, l = 0, 1,2 and 3. Hence, there are four subshells namely, s, p, d and f
l = 0, m₁ = 0; one 4s orbital, l = 1, m = -1, 0, +1; three 4p orbitals,
l = 2, m₁ = – 2, -1, 0, +1, +2; five 4d orbitals and
l = 3, m₁ = – 3, -2, -1, 0, 1, 2, 3; seven 4f orbitals. Hence, the number of possible orbitals when n = 4 are sixteen.

Question 28.
How many radial nodes for 25, 4p, 5d and 4f orbitals exhibit? How many angular nodes?
Answer:
The number of radial nodes is equal to (n – l – 1) and angular nodes is l.

Orbital	N	l	Radial node (n – l – 1)	Angular node, l
2s	2	0	1	0
4p	4	1	2	1
5d	5	2	2	2
4f	4	3	0	3

The number of radial nodes for 2s, 4p, 5d, and 4f orbitals are respectively 1,2,2 and 0 and the number of angular nodes for 2s, 4p, 5d, and 4f orbitals respectively are 0, 1, 2, and 3.

Question 29.
The stabilization of a half-filled d – orbital is more pronounced than that of the p-orbital. Why?
Answer:
The exactly half-filled orbitals have greater stability. The reason for their stability are –

1. symmetry
2. exchange energy.

(1) Symmetry: The half-filled orbitals are more symmetrical than partially filled orbitals and this symmetry leads to greater stability.

(2) Exchange energy: The electrons with the same spin in the different orbitals of the same sub-shell can exchange their position. Each such exchange releases energy and this is known as exchange energy. Greater the number of exchanges, the greater the exchange energy, and hence greater the stability. In d-orbital, 10 exchanges are possible but in p-orbital 6 exchanges are possible. So, d – orbital with 5 unpaired electrons (10 exchanges)n i.e. half-filled is more stable than p – orbital with 3 unpaired electrons (6 exchanges).

Question 30.
Consider the following electronic arrangements for the d⁵ configuration.

(i) Which of these represents the ground state?
(ii) Which configuration has the maximum exchange energy?
Answer:
(i) The ground state electronic configuration is

(ii) The configuration has the maximum exchange energy is

Question 31.
State and explain Paull’s exclusion principle.
Answer:
Pauli’s exclusion principle states that “No two electrons in an atom can have the same set of values of all four quantum numbers”.
Illustration: H(Z = 1) 1s¹.
One electron is present in hydrogen atom, the four quantum numbers are n = 1, l = 0, m = 0 and s = + \(\frac {1}{2}\). For helium Z = 2. He: 1s². In this one electron has the quantum number same as that of hydrogen, n = 1,l = 0, m = 0 and s = +½ For other electron, fourth quantum number is different, i.e. n = 1, l = 0, m = 0 and s = – ½.

Question 32.
Define orbital. What are ‘n’ and ‘l’ values for 3px and 4d _{x² – y²} electron?
Answer:
Orbital is a three-dimensional space in which the probability of finding the electron is maximum. The values of ‘n’ and ‘l’ for 3px orbital are n = 3 and l = 1, 4d _{x² – y²} orbital are n = 4 and l = 2.

Question 33.
Explain briefly the time-independent Schrodinger wave equation.
Answer:
Erwin Schrodinger expressed the wave nature of electrons in terms of a differential equation. This equation determines the change of wave function in space depending on the field of force in which the electron moves. The time-independent Schrodinger equation can be expressed as
Hψ = Eψ, where H is called Hamiltonian operator, ψ is the wave function and is a function of position coordinates of the particle and is denoted as ψ(x, y, z), E is the energy of the system.

The above Schrodinger wave equation does not contain time as a variable and is referred to as time-independent Schrodinger wave equation. This equation can be solved only for certain values of E, the total energy, i.e., the energy of the system is quantized. The permitted total energy values are called eigenvalues and corresponding wave functions represent the atomic orbitals.

Question 34.
Calculate the uncertainty in position of an electron, if ∆v = 0.1 % and υ = 2.2 × 10⁶ ms^-1.
Answer:
Heisenberg’s Uncertainty Principle is ∆x. ∆v > h/4πm.
Given:
∆v = 0.1%,
υ = 22 × 10⁶ ms^-1.
h = 6.626 × 10^-34 kgm²s^-1 .
m = 9.1 X 10 21 kg.
∆v = \(\frac{0.1 \times 2.2 \times 10^{6} \mathrm{~ms}^{-1}}{100}\)

= 2.2 × 10³ ms^-1
Uncertainty in position,
∆x ≥ \(\frac{h}{4 \pi m}\)
∆x ≥ \(\frac{6.626 \times 10^{-34} \mathrm{kgm}^{2} \mathrm{~s}^{-1}}{9.1 \times 10^{-31} \mathrm{~kg} . \times 2.2 \times 10^{3} \mathrm{~ms}^{-1}}\)

∆x ≥ 2.64 × 10^-8 m.

Question 35.
Determine the values of all the four quantum numbers of the 8th electron in the O – atom and 15th electron in the Cl atom and the last electron in Chromium.
Answer:
(1) O (Z = 8) 1s² 2s² 2p_x² 2p_y¹ 2p_z¹
Four quantum numbers for 2p_x¹ electron in oxygen atom:
n = principal quantum number = 2
l = azimuthal quantum number =1
m = magnetic quantum number =+1
s = spin quantum number = +\(\frac {1}{2}\)

(2) Cl (Z = 17) 1s² 2s² 2p⁶ 3s² 3p_x² 3p_y² 3p_z¹
Four quantum numbers for 15^th electron in chlorine atom:
n = 3, l = 1, m = 0, s = + ½

(3) Cr (Z = 24) 1s² 2s² 2p² 3s² 3p² 3d² 4s¹
n = 3, l = 2, m = +2, s = + ½

Question 36.
The quantum mechanical treatment of the hydrogen atom gives the energy value:
E_n = –\(\frac{-13.6}{n^{2}}\) eV/atom
(i) Use this expression to find ∆E between n = 3 and n = 4.
(ii) Calculate the wavelength corresponding to the above transition.
Answer:
Energy of the electron in the nth orbit is
E_n = –\(\frac{-13.6}{n^{2}}\)eV/atom.

When n = 3,
E₃ = \(\frac{-13.6 \mathrm{eV} / \text { atom }=-1.51 \mathrm{eV} / \text { atom }}{9}\)

When n = 4,
E₄ = \(\frac{-13.6 \mathrm{eV} / \text { atom }=-0.85 \mathrm{eV} / \text { atom }}{16}\)

∆E = (E₄ – E₃) = (-0.85) – (-1.51) = 0.66 eV/atom
Wavelength corresponding to this transition,

Question 37.
How fast must a 54g tennis ball travel in order to have a de Broglie wavelength that is equal to that of a photon of green light 5400 Å?
Answer:
de Broglie wavelength,
λ = \(\frac{h}{m v}\)
Given:
de Broglie wavelength, λ = 5400 Å and mass, m = 54 g.
Velocity of the tennis ball
v = \(\frac{h}{m \lambda}\)

v = \(\frac{6.626 \times 10^{-34} J s}{54 \times 10^{-3} k g \times 5400 \times 10^{-10} m}\)

v = 2.27 × 10^-26 ms^-1

Question 38.
For each of the following, give the sub level designation, the allowable m values and the number of orbitals,
(i) n = 1, l = 2
(ii) n = 5, l = 3
(iii) n = 7, l = 0
Answer:

Question 39.
Give the electronic configuration of Mn²⁺ and Cr³⁺.
Answer:
1. Mn (Z = 25)
Mn → Mn²⁺ + 2e^–
Mn²⁺ electronic configuration is 1s 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵

2. Cr (Z = 24)
Cr → Cr³⁺ + 3e^–
Cr³⁺ electronic configuration is Is² 2s² 2p⁶ 3s²3p⁶ 3d³

Question 40.
Describe the Aufbau principle.
Answer:
Aufbau Principle states that “In the ground state of the atoms, the orbitals are filled in the order of their increasing energies”. That is the electrons first occupy the lowest energy orbital available to them. Once the lower energy orbitals are completely filled, then the electrons enter the next higher energy orbitals. The order of filling of various orbitals as per the Aufbau principle is given in the figure. which is in accordance with the (n + l) rule.

Question 41.
An atom of an element contains 35 electrons and 45 neutrons. Deduce
(i) the number of protons
(ii) the electronic configuration for the element
(iii) All the four quantum numbers for the last electron.
Answer:
(i) Atomic Number of the element, z = No. of protons or No. of electrons. = 35
Mass number of the element, A = No. of protons + No of neutrons = 35 + 45 = 80
Number of Protons = 80 – 45 = 35.

(ii) Electronic configuration of the element (z = 35)
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵

(iii) Quantum number for the last electron (4p_z),
n = 4, l = 1, m = +1, or -1 s = +1/2

Question 42.
Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving around the nucleus.
Answer:
According to the de Broglie concept, the electron that revolves around the nucleus exhibits both particle and wave character. In order for the electron wave to exist in phase, the circumference of the orbit should be an integral multiple of the wavelength of the electron wave, Otherwise, the electron wave is out of phase.
Circumference of the orbit = nλ
2πr = nλ
2πr = \(\frac{n h}{m v}\)
Rearranging,
mvr = \(\frac{n h}{m v}\)
Angular momentum = \(\frac{n h}{2 \pi}\)
The above equation was already predicted by Bohr.
Hence, de Broglie and Bohr’s concepts are in agreement with each other.

Question 43.
Calculate the energy required for the process.
He⁺_(g) → He²⁺_(g) + e^–
The ionization energy for the H atom in its ground state is — 13.6 eV/atom.
Answer:
He⁺_(g) → He²⁺_(g) + e and
E_n = – 13.6z²/n²
E_l = – \(\frac{13.6(2)^{2}}{(1)^{2}}\) = -56.4 eV

E_∞ = \(\frac{-13.6(2)^{2}}{(\infty)^{2}}\) = 0

Required energy for the given process is,
E_∞ – E_l = 0 – (-56.4) = 56.4 eV.

Question 44.
An ion with mass number 37 possesses unit negative charge. It the ion contains 11.1% more neutrons than electrons. Find the symbol of the ion.
Answer:
Let the number of electrons in an ion = x
number of neutrons = n = x + \(\frac{11.1}{100}\) eV = 1.111 x
(As the number of neutrons is 11.1% more than the number of electrons)
In the neutral of the atom, a number of electrons.
e^– = x – 1 (as the ion carries -1 charge)
Similarly number of protons = P = x – 1
Number of protons + number of neutrons = mass number = 37
(x – 1) + 1.111 x = 37 .
2.111 x = 37 +1
2.111 x = 38
x = \(\frac{38}{2.111}\) = 18.009 = 18
∴ Number of protons = atomic number – 1 = 18-1 = 17
∴ The symbol of the ion = \(_{17}^{37} \mathrm{Cl}\).

Question 45.
The Li²⁺ ion is a hydrogen-like ¡on that can be described by the Bohr model. Calculate the Bohr radius of the third orbit and calculate the energy of an electron in 4th orbit.
Answer:

Question 46.
Protons can be accelerated in particle accelerators. Calculate the wavelength (in Å) of such accelerated proton moving at 2.85 × 10⁸ms^-1 (mass of proton is 1.673 × 10^-27 kg).
Answer:
Given:
velocity, v = 2.85 × 10⁸ms^-1.
mass, m = 1.673 × 10^-27 kg
λ = \(\frac{h}{m v}\)

λ = \(\frac{6.626 \times 10^{-34} \mathrm{kgms}^{-1}}{1.673 \times 10-27 \mathrm{~kg} \times 2-85 \times 10^{8} \mathrm{~ms}^{-1}}\)

λ = 1.389 × 10^-8 Å

Question 47.
What is the de Broglie wavelength (in cm) of a 160g cricket ball travelling at 140 Km hr^-1.
Answer:
Given:
velocity, v = 140 km/hr. = \(\frac{140 \times 10^{3}}{60 \times 60 \mathrm{~ms}^{-1}}\)

mass, m = 160g = 160 × 10^-3 kg
λ = \(\frac{h}{m v}\)
λ =\(\frac{6.626 \times 10^{-34} \mathrm{kgm}^{2} \mathrm{~s}^{-\mathrm{le}}}{160 \times 10^{-3} \mathrm{~kg} \times 3.88 \mathrm{~ms}^{-1}}\)

λ = 1.605 × 10^-34 m.

Question 48.
Suppose that the uncertainty in determining the position of an electron in an orbit is 0.6 Å. What is the uncertainty in its momentum?
Answer:
Heisenberg Uncertainity Principle is ∆x . ∆p ≥ \(\frac{h}{4 \pi}\)
Given:
∆x = 0.6 Å = 0.6 × 10^-10 m
h = 6.626 × 10^-34 kgm²s^-1
Uncertainity in momentum,
∆p ≥ \(\frac{h}{4 \pi \Delta x}\)

∆p ≥ \(\frac{6.626 \times 10^{-34} \mathrm{kgm}^{2} \mathrm{~s}^{-1}}{4 \times 3.14 \times 0.6 \times 10^{-10} \mathrm{~m}}\)

∆p ≥ 8.8 × 10^-25 kgms^-1

Question 49.
Show that if the measurement of the uncertainty in the location of the particle is equal to its de Broglie wavelength, the minimum uncertainty in its velocity (∆V) is equal to 1/4π of its velocity(V)
Answer:

Question 50.
What is the de Brogue wave length of an electron, which is accelerated from the rest, through a potential difference of 100V?
Answer:
Potential difference = 100 V = 100 × 106 × 10^-19 J
λ = \(\frac{h}{\sqrt{2} \text { mev }}\)

λ = \(\frac{6.626 \times 10^{-34} \mathrm{Kgm}^{2} \mathrm{~s}}{\sqrt{2} \times 9.1 \times 10^{-31} \mathrm{~kg} \times 100 \times 1.6 \times 10^{-19} \mathrm{~J}}\)

λ = 1.22 × 10^-10

Question 51.
Identify the missing quantum numbers and the sub energy level.

Answer:

11th Chemistry Guide Quantum Mechanical Model of Atom Additional Questions and Answers

I. Choose the best Answer:

Question 1.
The angular momentum of the electron in the nth orbit is
(a) \(\frac{\pi h}{2 n}\)

(b) \(\frac{2 n h}{\pi}\)

(c) \(\frac{n h}{2 \pi}\)

(d) \(\frac{2 \pi}{n h}\)
Answer:
(c) \(\frac{n h}{2 \pi}\)

Question 2.
The frequency of radiation emitted when an electron jumps from higher energy state (E₂) to a lower energy state (E₁) is given by
(a) v = \(\frac{\left(E_{2}+E_{1}\right)}{h}\)

(b) v = \(\frac{\left(E_{1}+E_{2}\right)}{h}\)

(c) v = \(\frac{\left(E_{1}-E_{2}\right)}{h}\)

(d) v = \(\frac{\left(E_{2}-E_{1}\right)}{h}\)
Answer:
(d) v = \(\frac{\left(E_{2}-E_{1}\right)}{h}\)

Question 3.
Splitting of spectral lines in the presence of a magnetic field is called
(a) Zeeman effect
(b) Stark effect
(e) shielding effect
(d) Compton effect
Answer:
(a) Zeeman effect

Question 4.
Which one of the following has zero rest mass?
(a) electron
(b) proton
(c) neutron
(d) photon
Answer:
(d) photon

Question 5.
For a microscopic particle such as an electron, the mass is of the order of
(a) 10^-29 kg
(b) 10^-31 kg
(c) 10³¹ kg
(d) 10^-30 kg
Answer:
(b) 10^-31 kg

Question 6.
Which one of the following has insignificant de Broglie wavelength?
(a) electron
(b) proton
(e) neutron
(d) iron ball
Answer:
(d) iron ball

Question 7.
Which of the following statements are true about de Broglie wavelength?
(i) The particle travels at a speed much higher than the speed of light.
(ii) The particle can have high linear momentum.
(iii) The mass of the particle is of the order of 10^-30 kg.
(iv) The particle travels at speed much less than the speed of light.
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (ii) and (iv)
Answer:
(b) (iii) and (iv)

Question 8.
The correct mathematical expression/s for Heisenberg Uncertainty principle is
(i) ∆x . ∆p ≥ \(\frac{h}{4 \pi}\)

(ii) ∆x . ∆p ≥ \(\frac{h}{4 \pi m}\)

(iii) ∆x . ∆v ≥ \(\frac{h}{4 \pi m}\)

(iv) ∆x . ∆v ≥ \(\frac{h}{4 \pi}\)
(a) (i) and (ii)
(b) (ii) and(iv)
(c) (i) and (iii)
(d) (ii) and (iii)
Answer:
(c) (i) and (iii)

Question 9.
The wave nature of electron was experimentally confirmed by
(a) Louis de Broglie
(b) Davisson and German
(c) Schrodinger
(d) Niels Bohr
Answer:
(b) Davisson and German

Question 10.
The term ‘ ψ ’ in the Schrodinger equation is
(a) Eigenvalue
(b) Hamiltonian operator
(c) Wave function
(d) all of these
Answer:
(c) Wave function

Question 11.
The permitted total energy values in the Schrodinger equation are called
(a) eigenvalues
(b) eigen functions
(c) wave functions
(d) Hamiltonian operator
Answer:
(a) eigenvalues

Question 12.
_______ is a three-dimensional space in which the probability of finding the electron is maximum.
(a) orbit
(b) Orbital
(c) wave function
(d) eigenvalue
Answer:
(b) Orbital

Question 13.
Which of the following has always positive value?
(a) ψ
(b) ψ²
(c) both ψ and ψ²
(d) ψ³
Answer:
(b) ψ²

Question 14.
The maximum number of electrons that can be accommodated in M shell is
(a) 8
(b) 32
(c) 16
(d) 18
Answer:
(d) 18

Question 15.
The maximum number of electrons that can be accommodated in a given subshell is
(a) (2l + 1)
(b) 4l + 2
(c) l + 2
(d) 2(l + 1)
Answer:
(b) 4l + 2

Question 16.
The region where the probability density function reduces to zero is called
(a) wave function
(b) orbital
(c) nodal surface
(d) probability density region
Answer:
(c) nodal surface

Question 17.
Number of subshells and electrons associated with n = 4 respectively are
(a) 4, 16
(b) 32, 64
(c) 16, 32
(d) 8, 16
Answer:
(c) 16, 32

Question 18.
The radial wave function in the ψ(r, θ, φ) = R(r), f(θ), g(φ) is
(a) f(θ)
(b) g(φ)
(c) R(r)
(d) f(θ) and g(φ)
Answer:
(c) R(r)

Question 19.
The plot of _______ shows the maximum probability that occurs at a distance of 0.52 Å from the nucleus.
(a) 4π²r² vs ψ²
(b) 4π² r² ψ² vs r²
(c) 4π² ψ² vs r
(d) 4π² ψ² vs r²
Answer:
(d) 4π² ψ² vs r²

Question 20.
The number of radial nodes for a 3s orbital is
(a) 3
(b) 2
(c) 1
(d) 0
Answer:
(b) 2

Question 21.
The number radial nodes for a ‘nd’ orbital is
(a) (n – 1)
(b) (n – l)
(c) (n – l + 1)
(d) (n – l – 1)
Answer:
(d) (n – l – 1)

Question 22.
The order of the effective nuclear charge felt by an electron in an orbital within a shell is
(a) s < p < d < f
(b) s > p > d > f
(c) s < p ≈ d < f
(d) s ≈ p > d ≈ f
Answer:
(b) s > p > d > f

Question 23.
Which of the following sequences shows the correct increasing order of energy’?
(a) 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p
(b) 3s, 3p, 4s, 4p, 3d, 5s, 4d, 5p
(c) 3s, 3p, 4s, 4p, 3d, 5s, 5p, 4d
(d) 3s, 3p, 4s, 4p, 3d, 4d, 5s, 5p
Answer:
(a) 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p

Question 24.
The orbital with following quantum numbers (i) n = 4,1 = 3 and (ii) n = 3 and 1 = 2 are
(a) 3d, 4f
(b) 3d, 4d
(c) 3f, 4f
(d) 3p, 4f
Answer:
(c) 3f, 4f

Question 25.
The energy of one photon of a beam of light with wavelength 3.31 × 10^-6 m is
(a) 6 × 10^-20 J
(b) 2 × 10^-20 J
(c) 6 × 10^-21 J
(d) 2 × 10^-21 J
Answer:
(a) 6 × 10^-20 J

Question 26.
The ratio of energies of two radiations with wavelengths of 300 nm and 900 nm is
(a) 1 : 3
(b) 2 : 1
(c) 3 : 1
(d) 1 : 2
Answer:
(c) 3 : 1

Question 27.
The momentum of a particle which has a wavelength of 6.62 Å is (in kg ms^-1)
(a) 10^-20
(b) 10^-22
(c) 10^-34
(d) 10^-24
Answer:
(d) 10^-24

Question 28.
If the energy difference between the ground state of an atom and its excited state is 3.31 × 10^-19 J, the wavelength of the photon required to produce this transition is
(a) 3 × 10^-9 m
(b) 6 × 10^-7 m
(c) 3 × 10^-8 m
(d) 6 × 10^-6 m
Answer:
(b) 6 × 10^-7 m

Question 29.
The spectrum of He⁺ is similar to
(a) Li⁺
(b) H⁺
(c) He
(d) Li²⁺
Answer:
(c) He

Question 30.
An atom has two electrons in the K shell, eight electrons in the L shell, and eight electrons in the M shell. The number of ‘s’ electrons present in that element is
(a) 18
(b) 10
(c) 6
(d) 4
Answer:
(c) 6

Question 31.
The atomic number of an element ‘A’ is 25. How many electrons are present in the third shell of the element in its A³⁺ state?
(a) 10
(b) 12
(c) 15
(d) 4
Answer:
(b) 12

Question 32.
Which of the following sets of quantum numbers are not possible?

(a) (i), (iii) and (iv)
(b) (i), (iv) and (v)
(c) (iii), (iv) and (v)
(d) (i), (ii) and (iii)
Answer:
(c) (iii), (iv) and (v)

Question 33.
ψ² is always
(a) negative
(b) positive
(c) either positive or negative
(d) none of these
Answer:
(b) positive

Question 34.
Which of the following sets of quantum numbers represents the highest energy of an atom?
(a) n = 4, l = 1, m = 0, s = +1/2
(b) n = 3, l = 0, m = 0, s = +1/2
(c) n = 3, l = 0, m = 1, s = +1/2
(d) n = 4, l = 0, m = 0, s = +1/2
Answer:
(a) n = 4, l = 1, m = 0, s = +1/2

Question 35.
The number of possible exchanges for [Ar] 3d⁴ 4s² configuration is
(a) 10
(b) 6
(c) 4
(d) 1
Answer:
(b) 6

II. Very Short Question and Answers (2 Marks):

Question 1.
Write a note about J.J. Thomson’s atomic model.
Answer:

• J.J. Thomson’s cathode ray experiment revealed that atoms consist of negatively charged particles called electrons.
• He proposed that an atom is a positively charged sphere in which the electrons are embedded like the seeds in the watermelon.

Question 2.
What is the Zeeman effect?
Answer:
The splitting of spectral lines in the presence of a magnetic field is called the Zeeman effect.

Question 3.
What is Stark effect?
Answer:
The splitting of spectral lines in the presence of electric field is called Stark effect.

Question 4.
Write the limitation of Bohr’s postulates?
Answer:
Bohr’s postulates are applicable to one electron speciesvsuch as H, He⁺ and Li²⁺ etc.,

Question 5.
Write the formulae for the radius and energy of electron in the nth orbit of electron.
Answer:
Radius of electron in the nth orbit,

Question 6.
Write de Broglie equation and explain the terms in it.
Answer:
de Beoglie equation is λ = \(\frac{h}{m v}\)
where λ = de Broglie wavelength of matter waves, m = mass of the particle and v = velocity.

Question 7.
What are quantum numbers?
Answer:

• The electron in an atom can be characterized by a set of four quantum numbers, namely principal quantum number (n), azimuthal quantum number (l), magnetic quantum number (m), and spin quantum number (s).
• When the Schrodinger equation is solved for a wave function T, the solution contains the first three quantum numbers n, l, and m.
• The fourth quantum number arises due to the spinning of the electron about its own axis.

Question 8.
State Heisenberg Uncertainty principle.
Answer:
It is impossible to accurately determine both the position as well as the momentum of a microscopic particle simultaneously.

Question 9.
What is classical mechanics?
Answer:
The motion of objects that we come across in our daily life can be well described based on Newton’s law of motion is called classical mechanics.

Question 10.
What is the limitation of classical mechanics?
Answer:
Classical mechanics does not consider the dual nature of the matter which is significant for microscopic particles. As a consequence, it fails to explain the motion of microscopic particles.

Question 11.
What is quantum mechanics?
Answer:
Based on Heisenberg’s principle and the dual I nature of the microscopic particles, a new mechanics I developed to study the motion of microscopic particles is called quantum mechanics.

Question 12.
What is Schrodinger’s equation?
Answer:
Erwin Schrodinger expressed the wave nature of electron in terms of the differential equation is called Schrodinger equation. This equation determines the change of wave equation in space depending on the field of force in which the electron moves.

Question 13.
Write the Schrodinger equation in terms of the operator?
Answer:
The time-independent Schrodinger equation can be expressed as Hψ = Eψ
where H is called Hamiltonian operator, ψ is the wave function and E is the energy of the system.

Question 14.
Write the Schrodinger equation in terms of a differential equation?
Answer:
The time independent Schrodinger equation in terms of a differential equation is
\(\frac{\partial^{2} \Psi}{\partial x^{2}}+\frac{\partial^{2} \Psi}{\partial y^{2}}+\frac{\partial^{2} \Psi}{\partial z^{2}}+\frac{8 \pi^{2} m}{h^{2}}(\mathrm{E}-\mathrm{V}) \Psi=0\)

Question 15.
What is a Hamiltonian operator?
Answer:
The total energy operator is called Hamiltonian operator and it can be expressed as
Ĥ = [latex]\frac{-h^{2}}{8 \pi^{2} m}\left(\frac{\partial^{2}}{\partial x^{2}}+\frac{\partial^{2}}{\partial y^{2}}+\frac{\partial^{2}}{\partial z^{2}}\right)+V[/latex]

Question 16.
Define an orbital.
Answer:
Orbital is a three-dimensional space in which the probability of finding the electron is maximum.

Question 17.
Calculate the total number of angular nodes and radial nodes present in 4p and 4d orbitals.
Answer:
1. For 4p orbital:
Number of angular nodes = l
For 4p orbital 7 = l
Number of angular nodes = l
Number of radial nodes = n – l – 1 = 4 -1 -1 = 2
Total number of nodes = n -1 = 4 – 1 = 3
1 angular node and 2 radial nodes.

2. For 4d orbital:
Number of angular nodes = l
For 4d orbital l = 2
Number of angular nodes = 2
Number of radial nodes = n – l – 1 = 4 – 2 – 1 = 1
Total number of nodes = n – l = 4 – l = 3
1 radial nodes and 2 angular node.

Question 18.
The energies of the same orbital decrease with an increase in the atomic number. Justify this statement.
Answer:
The energy of the 2s orbital of a hydrogen atom is greater than that of 2s orbital of lithium and that of lithium is greater than that of sodium and so on because of H (Z =1), Li (Z = 3), and Na (Z = 11). When the atomic number increases, the energies of the same orbital decrease. E_2s(H) > E_2s(Li) > E_2s(Na) > E_2s(K) ………….

Question 19.
What is the principal quantum number?
Answer:
The principal quantum number represents the energy level in which an electron revolving around the nucleus and is denoted by the symbol ‘n’.

Question 20.
What is a nodal surface or a radial node?
Answer:
The region where this probability density function reduces to zero is called nodal surface or a radial node.

Question 21.
What is the significance of the solution to the Schrodinger equation?
Answer:
The solution to the Schrodinger equation gives the permitted energy values called eigenvalues and the wave functions corresponding to the eigenvalues are called atomic orbitals.

Question 22.
What are radial and angular wave functions?
Answer:
The solution of the Schrodinger wave equation for one electron system can be expressed in spherical polar coordinates as ψ(r, θ, φ) = R(r). f(θ). g(φ) Where R(r) is called a radial wave function, f(θ) and g(φ) are called angular wave functions.

Question 23.
What is the ground state?
Answer:
The electron present in the lowest energy state is called the ground state.

Question 24.
State (n + l) rule.
Answer:
The lower the value of (n + l) for an orbital, the lower is its energy. If two orbitals have the same value of (n + l), the orbital with lower value of ‘n’ will have the lower energy.

III. Short Question and Answers (3 Marks):

Question 1.
What are the conclusions of Rutherford’s α – rays scattering experiment?
Answer:

• Rutherford bombarded a thin gold foil with a stream of fast-moving α – particles.
• It was observed that most of the a-particles passed through the foil.
• Some of them were deflected through a small angle.
• Very few α- particles were reflected back by 180°.
• Based on these observations, he proposed that in an atom, there is a tiny positively charged nucleus and the electrons are moving around the nucleus with high speed.

Question 2.
Write the assumptions of Bohr’s atom model.
Answer:
Bohr’s atom model is based on the following assumptions:
(i) The energies of electrons are quantized.
(ii) The electron is revolving around the nucleus in a certain fixed circular path called stationary orbit.
(iii) Electron can revolve only in those orbitsJn which the angular momentum {mvr) of the electron must be equal to an integral multiple of \(\frac{h}{2 \pi}\)
i,e., mvr = \(\frac{n h}{2 \pi}\), where n = 1, 2, 3, … etc.,
(iv) As long as an electron revolves in the fixed orbit, it does lose its energy. However, when an electron jumps from higher energy state (E₂) to a lower energy state (E¹), the excess energy is emitted as radiation.
The frequency of the emitted radiation is (E₂ – E₁) = hυ.

Frequency, υ = \(\frac{\left(E_{2}-E_{1}\right)}{h}\)
Conversely, when suitable energy is supplied to an electron, it will jump from lower energy orbit to a higher energy orbit.

Question 3.
Explain Davisson and Germer’s experiment.
Answer:

• The wave nature of electrons was experimentally confirmed by Davisson and Germer.
• They allowed the accelerated beam of electrons to fall on a nickel crystal and recorded the diffraction pattern.
• The resultant diffraction pattern is similar to the X-ray diffraction pattern.
• The finding of wave nature of electron leads to the development of various experimental techniques such as electron microscope, low energy electron diffraction, etc.

Question 4.
Show that de Broglie and Bohr’s concepts are in agreement with each other.
Answer:
According to the de Broglie concept, the electron that revolves around the nucleus exhibits both particle and wave character. In order for the electron wave to exist in phase, the circumference of the orbit should be an integral multiple of the wavelength of the electron wave, Otherwise, the electron wave is out of phase.
Circumference of the orbit = nλ
2πr = nλ
2πr = \(\frac{n h}{m v}\)
Rearranging,
mvr = \(\frac{n h}{2 \pi}\)
Angular momentum = \(\frac{n h}{2 \pi}\)
The above equation was already predicted by Bohr. Hence, de Broglie and Bohr’s concepts are in agreement with each other.

Question 5.
Write a note about the principal quantum number.
Answer:

• The principal quantum number represents the energy level in which an electron revolves around the nucleus and is denoted by the symbol ‘n’.
• The ‘n’ can have the values 1, 2, 3,… n = 1 represents K shell; n=2 represents L shell and n = 3, 4, 5 represent the M, N, O shells, respectively.
• The maximum number of electrons that can be accommodated in a given shell is 2n².
• ‘n’ gives the energy of the electron,

E_n = \(\frac{(-1312.8) Z^{2}}{n^{2}}\) KJ mol^-1 and the distance of the electron from the nucleus is given by r_n = \(\frac{(-0.529) n^{2}}{Z}\) A.

Question 6.
Write the significance of principle quantum number.
Answer:
Principle quantum number represents the energy level in which electron revolves around the nucleus and is denoted by the symbol ‘n’.
(i) The ‘n’ can have the values 1, 2, 3, … n = 1 represent K shell: n = 2 represents L shell and n = 3, 4, 5 represent the M, N, O shells respectively.
(ii) The maximum number of electrons that can be accommodated in a given shell, is 2n².
(iii) ‘n’ gives the energy of the electron,
E_n = \(\frac{(-1312.8) Z^{2}}{n^{2} k J m o l^{-1}}\)

and the distance of the electron from the nucleus is given by
r_n = \(\frac{(0.529) n^{2}}{Z}\) Å.

Question 7.
Write notes on Azimuthal Quantum number.
Answer:
(i) Azimuthal quantum number is represented by the letter ‘l’ and can take integral values from zero to (n – l), where n is the principle quantum number.
(ii) Each l value represents a subshell. l = 0, 1,2, 3 and 4 represents the s, p, d, f and g orbitals respectively.
(iii) The maximum number of electrons that can be accommodated in a given subshell is 2 (2l + 1).
(iv) It is used to calculate the orbital angular momentum using the expression
Angular momentum = \(\frac{\sqrt{l(l+1) h}}{2 \pi}\)

Question 8.
Write the significance of magnetic quantum numbers.
Answer:
(i) Spin quantum number is denoted by the letter ‘ml’. It takes integral values ranging from -l to +l through 0. i.e., if l = 1: m = -1, 0 and +1.
(ii) Different values of m for a given l value, represent different orientations of orbitals in space.
(iii) The Zeeman effect provides the experimental justification for this quantum number.
(iv) The magnitude of the angular momentum is determined by the quantum number ‘l’ while its direction is given by magnetic quantum number.

Question 9.
Write notes on spin quantum number.
Answer:
(i) The spin quantum number represents the spin of the electron and is denoted by the letter ‘m_s‘.
(ii) The electron in an atom revolves not only around the nucleus but also spins. It is usual to write this as an electron spins about its own axis either in a clockwise direction or in an anti-clockwise direction. The visualization is not true. However, spin is to be understood as representing a property that revealed itself in magnetic fields.
(iii) Corresponding to the clockwise and anti¬clockwise spinning of the electron, a maximum of two values are possible for this quantum number.
(iv) The values of ‘m_s‘ is equal to -1/2 and +1/2.

Question 10.
Write the significance of ψ and ψ².
Answer:
The wave function ψ has no physical meaning and the square of the wave function |ψ|² is related to the probability of finding the electrons within a given volume of space. |ψ|² varies with the distance from nucleus (radial distribution of the probability) and the direction from the nucleus (angular distribution of the probability).

Question 11.
Show that the probability of finding the electron is independent of the direction from the nucleus.
Answer:
The variation of the probability of locating the electron on a sphere with nucleus at its centre depends on the azimuthal quamtum number of the orbital in which the electron is present. For 1s orbital, l = 0, and m = 0.
f(θ) = \(\frac{1}{\sqrt{2}}\) and g(φ) = \(\frac{1}{\sqrt{2 \pi}}\)

Therefore, the angular distribution function is equal to \(\frac{1}{2 \sqrt{\pi}}\) i.e., it is independeent of the angle θ and φ. Hence, the probability of finding the electron is independent of the direction from the nucleus.

Question 12.
Sketch the shapes of 1s, 2s and 3s orbitals.
Answer:

Question 13.
Sketch and explain the shapes of p-orbitals.
Answer:
The shape of the p-orbitais are shown in figure, For p orbitaIs, l = 1 and the corresponding m values are -1, 0 and +1. The three different ‘m’ values indicates that there are three different orientations possible for p orbitals. These orbitals are designated as p_x, p_y and p_z and the angular distribution for these orbitals shows that the lobes are along the x, y and z axis respectively.

Question 14.
What are ground and excited states?
Answer:
The electron in the hydrogen atom occupies the ly orbital that has the lowest energy. This state is called ground state. When this electron gains some energy, it moves to the higher energy orbitals such as 2s, 2p etc., These states are called excited states.

Question 15.
Explain the significance of effective nuclear charge.
Answer:
In a multi-electron atom, in addition to the electrostatic attractive force between the electron and nucleus, there exists a repulsive force among the electrons. These two forces are operating in the opposite direction. This results in the decrease in the nuclear force of attraction on electron.
The net charge experienced by the electron is called effective nuclear charge. The effective nuclear charge depends on the shape of the orbitals and it decreases with increase in azimuthal quantum number l. The order of the effective nuclear charge felt by a electron in an orbital within the given shell is s > p > d > l.

Greater the effective nuclear charge, greater is the stability of the orbital. Hence, within a given energy level, the energy of the orbitals are in the following order s < p < d <f.

Question 16.
State and explain Hund’s rule.
Answer:
Hund’s rule of maximum multiplicity states that- electron pairing in the degenerate orbitals does not take place until all the available orbitals contains one electron each. Consider the carbon atom which has six electrons. According to Aufbau principle, the electronic configuration is 1s², 2s², 2p².
It can be represented as below,

In this case, in order to minimize the electron- electron repulsion, the sixth electron enters the unoccupied 2py orbital as per Hund’s rule, i.e., it does not get paired with the fifth electron already present in the 2px orbital.

IV. Long Question and Answers:

Question 1.
Derive de Broglie equation.
Answer:
Albert Einstein proposed that light has dual nature. i.e., light photons behave both like a particle and as a wave. Louis de Broglie extended this concept and proposed that all forms of matter showed dual character. To quantify this relation, he derived an equation for the wave length of a matter wave. He combined the following two equations of energy of which one represents wave character (hυ) and the other represents the particle nature (mc²).
Planck’s quantum hypothesis is
E = hυ ………..(1)
Einstein’s mass-energy relationship,
E = mc²
From (1) and (2), hυ = mc²
\(\frac{h c}{\lambda}\) = mc²
λ = \(\frac{h}{m c}\)
Equation (3) represents the wavelength of photons whose momentum is given by mc. For a particle of matter with mass ‘m’ and moving with a velocity ‘v’, the equation (3) can be written as
λ = \(\frac{h}{m v}\) …………..(4)

The equation (4) is called de Broglie equation for matter waves and this is valid only when the particle travels at speeds much less than the speed of light. This equation implies that a moving particle can be considered as a wave and a wave can exhibit the properties of a particle.

For a particle with high linear momentum the wavelength will be so small and cannot be observed. For a microscopic particle such as an electron, the mass is of the order of 10^-31 kg, hence the wavelength is much larger than the size of atom and it becomes significant.

Question 2.
Write the main features of the quantum mechanical model of atom.
Answer:
(i) The energy of electrons in atoms is quantized.
(ii) The existence of quantized electronic energy levels is a direct result of the wave-like properties of electrons.
(iii) According to Heisenberg uncertainty principle, the exact position and momentum of an electron cannot be determined with absolute accuracy. As a consequence, quantum mechanics introduced the concept of orbital. Orbital is a three dimensional space in which the probability of finding the electron is maximum.
(iv) The solution of Schrodinger wave equation for the allowed energies of an atom gives the wave function, ψ, which represents an atomic orbital. The wave nature of electron present in an orbital can be well defined by the wave function ψ.
(v) The wave function, ψ, itself has no physical meaning. However, the probability of finding the electron in a small volume dxdydz around a point (x, y, z) is proportional to |ψ(x, y, z)|² dxdydz. |ψ(x, y, z)|² is known as probability density and is always positive.

Question 3.
Describe the radial distribution function of 1s and 2s orbitals of hydrogen atom.
Answer:
Consider a single electron of hydrogen atom in the ground state for which the quantum numbers are n = 1 and l = 0. i.e., it occupies l.y orbital. The plot R(r)² versus r for is orbital given in figure.

The graph shows that as the distance between the electron and the nucleus decreases, the probability of finding the electron increases. At r = 0, the quantity R(r)² is maximum. The maximum value for |ψ|² is at the nucleus. However, probability of finding the electron in a given spherical shell around the nucleus is important. Let us consider the volume (dV) bounded by two spheres of radii r and r + dr.

The above plot shows that the maximum probability occurs at distance of 0.52 Å. from the nucleus. This is equal to the Bohr radius. It indicates that the maximum probability of finding the electron around the nucleus is at this distance. However, there is a probability to find the electron at other distances also. The radial distribution function of 2s, orbital of the hydrogen atom represented as follows.

Question 4.
Sketch and explain the shapes of d-orbitals.
Answer:
For ‘d’ orbital l = 2 and the corresponding ‘m’ values are -2, -1, 0, +1, +2. The shape of the ‘d’ orbital looks like a ‘clover leaf’. The five m values give rise to five d orbitals namely d_xy, d_yz, d_zx, d_{x² – y²}, and d_z². The 3d orbitals contain two nodal planes as shown in figure.

Question 5.
Sketch and explain the shapes of f-orbitals.
Answer:
For ‘f orbitals, l = 3 and the m values are -3, -2, -1, 0, +1, +2, +3 corresponding to seven f orbitals which are shown in figure. There are three nodal planes in the f orbitals.

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Computer Science Guide Pdf Chapter 13 Introduction to Object-Oriented Programming Techniques Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Computer Science Solutions Chapter 13 Introduction to Object-Oriented Programming Techniques

11th Computer Science Guide Introduction to Object-Oriented Programming Techniques Text Book Questions and Answers

Book Evaluation

Part I

Choose The Correct Answer

Question 1.
The term is used to describe a programming approach based on classes and objects is
a) OOP
b) POP
c) ADT
d) SOP
Answer:
a) OOP

Question 2.
The paradigm which aims more at procedures.
a) Object Oriented Programming
b) Procedural programming
c) Modular programming
d) Structural programming
Answer:
b) Procedural programming

Question 3.
Which of the following is a user defined data type?
a) class
b) float
c) int
d) object
Answer:
a) class

Question 4.
The identifiable entity with some characteristics and behaviour is.
a) class
b) object
c) structure
d) member
Answer:
b) object

Question 5.
The mechanism by which the data and functions are bound together into a single unit is known as
a) Inheritance
b) Encapsulation
c) Polymorphism
d) Abstraction
Answer:
b) Encapsulation

Question 6.
Insulation of the data from direct access by the program is called as
a) Data hiding
b) Encapsulation
c) Polymorphism
d) Abstraction
Answer:
a) Data hiding

Question 7.
Which of the following concept encapsulate all the essential properties of the object that are to be created?
a) class
b) Encapsulation
c) Polymorphism
d) Abstraction
Answer:
d) Abstraction

Question 8.
Which of the following is the most important advantage of inheritance?
a) data hiding
b) code reusability
c) code modification
d) accessibility
Answer:
b) code reusability

Question 9.
“Write once and use it multiple time” can be achieved by
a) redundancy
b) reusability
c) modification
d) composition
Answer:
b) reusability

Question 10.
Which of the following supports the transitive nature of data?
a) Inheritance
b) Encapsulation
c) Polymorphism
d) Abstraction
Answer:
a) Inheritance

Part – II

Very Short Answer

Question 1.
How is modular programming different from the procedural programming paradigm?
Answer:
Modular programming:

• Emphasis on the algorithm rather than data.
• Programs are divided into individual modules.
• Each modules are independent of each other and have their own local data.
• Modules can work with their own data as well as with the data passed to it.

Procedural programming:

• Programs are organized in the form of subroutines or subprograms.
• All data items are global.
• Suitable for a small-sized software applications.
• Difficult to maintain and enhance the program code as any change in data type needs to be propagated to all subroutines that use the same data type.

Question 2.
Differentiate classes and objects.
Answer:
Class: A Class is a construct in C++ which is used to bind data and its associated function together into a single unit using the encapsulation concept. Class is a user-defined data type.

Object: An identifiable entity with some characteristics and behaviour is called an object.

Question 3.
What is polymorphism?
Answer:
Polymorphism is the ability of a message or function to be displayed in more than one form.

Question 4.
How are encapsulation and abstraction are interrelated?
Answer:
The mechanism by which the data and functions are bound together into a single unit is known as Encapsulation. It implements abstraction.
Abstraction refers to showing only the essential features without revealing background details.

Question 5.
Write the disadvantages of OOP.
Answer:

1. Size: Object-Oriented Programs are much larger than other programs.
2. Effort: Object-Oriented Programs require a lot of work to create.
3. Speed: Object-Oriented Programs are slower than other programs, because of their size.

Part – III

Short Answers

Question 1.
What is a paradigm? Mention the different types of paradigm.
Answer:
The paradigm means organizing principle of a program. It is an approach to programming.
There are different approaches available for problem-solving using computers. They are:

• Procedural programming,
• Modular Programming and
• Object-Oriented Programming.

Question 2.
Write a note on the features of procedural programming.
Answer:
Important features of procedural programming

1. Programs are organized in the form of subroutines or subprograms
2. All data items are global
3. Suitable for small-sized software application
4. Difficult to maintain and enhance the program code as any change in data type needs to be propagated to all subroutines that use the same data type. This is time-consuming.
5. Example: FORTRAN and COBOL.

Question 3.
List some of the features of modular programming
Answer:
Important features of modular programming:

• Emphasis on the algorithm rather than data.
• Programs are divided into individual modules.
• Each modules are independent of each other and have their own local data.
• Modules can work with its own data as well as with the data passed to it.
• Example: Pascal and C.

Question 4.
What do you mean by modularization and software reuse?
Answer:

1. Modularization: where the program can be decomposed into modules.
2. Software reuse: where a program can be composed of existing and new modules.

Question 5.
Define information hiding.
Answer:
The data is not accessible to the outside world, and only those functions which are wrapped in the class can access it.These functions provide the interface between the object’s data and the program.
This encapsulation of data from direct access by the program is called data hiding or information hiding.

Part-IV

Explain in Detail

Question 1.
Write the differences between object-oriented programming and procedural programming.
Answer:
Object-Oriented Programming:

• Emphasizes data rather than algorithms.
• Data abstraction is introduced in addition to procedural abstraction.
• Data and its associated operations are grouped into a single unit.
• Programs are designed around the data being operated.
• Example: C++, Java, VB.Net, Python

Procedural Programming:

• Programs are organized in the form of subroutines or subprograms.
• All data items are global.
• Suitable for a small-sized software application.
• Difficult to maintain and enhance the program code as any change in data type needs to be propagated to all subroutines that use the same data type.
• Example: FORTRAN and COBOL

Question 2.
What are the advantages of OOPs?
Answer:
Advantages of OOP Re-usability:
“Write once and use it multiple times” you can achieve this by using class.

Redundancy:
Inheritance is a good feature for data redundancy. If you need the same functionality in multiple classes you can write a common class for the same functionality and inherit that class to sub-class.

Easy Maintenance:
It is easy to maintain and modify existing code as new objects can be created with small differences to existing ones.

Security:
Using data hiding and abstraction only necessary data will be provided thus maintains the security of data.

Question 3.
Write a note on the basic concepts that support OOPs?
Answer:
Object-Oriented Programming has been developed to overcome the drawbacks of procedural and modular programming. It is widely accepted that object-oriented programming is the most important and powerful way of creating software.

The Object-Oriented Programming approach mainly encourages:

1. Modularization: where the program can be decomposed into modules.
2. Software reuse: where a program can be composed of existing and new modules.

Main Features of Object-Oriented Programming:

1. Data Abstraction
2. Encapsulation
3. Modularity
4. Inheritance
5. Polymorphism

Encapsulation:
The mechanism by which the data and functions are bound together into a single unit is known as Encapsulation. It implements abstraction. Encapsulation is about binding the data variables and functions together in class. It can also be called data binding. Encapsulation is the most striking feature of a class.

The data is not accessible to the outside world, and only those functions which are wrapped in the class can access it. These functions provide the interface between the object’s data and the program. This encapsulation of data from direct access by the program is called data hiding or information hiding.

Data Abstraction:
Abstraction refers to showing only the essential features without revealing background details. Classes use the concept of abstraction to define a list of abstract attributes and function which operate on these attributes. They encapsulate all the essential properties of the object that are to be created. The attributes are called data members because they hold information. The functions that operate on these data are called methods or member functions.

Modularity:
Modularity is designing a system that is divided into a set of functional units (named modules) that can be composed into a larger application.

Inheritance:
Inheritance is the technique of building new classes (derived class) from an existing class (base class). The most important advantage of inheritance is code reusability.

Polymorphism:
Polymorphism is the ability of a message or function to be displayed in more than one form.

11th Computer Science Guide Introduction to Object-Oriented Programming Techniques Additional Questions and Answers

Choose The Correct Answer (1 Mark)

Question 1.
In procedural programming all data items are ……………….
(a) Cobol
(b) global
(c) fortran
(d) class
Answer:
(b) global

Question 2.
The object-oriented paradigm allows us to organize software as a collection of objects that consist of …………………..
a) Data
b) Behaviour
c) Both data and behaviour
d) None of these
Answer:
c) Both data and behaviour

Question 3.
………………. is an example of object-oriented programming.
(a) Python
(b) Java
(c) VB.Net
(d) All the above
Answer:
(d) All the above

Question 4.
Paradigm means ………………..
a) Organizing principle of a program
b) An approach to programming
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 5.
………………. is about binding the data variables and functions together in class.
(a) Data abstraction
(b) Modularization
(c) Redundancy
(d) Encapsulation
Answer:
(d) Encapsulation

Question 6.
In ………………. approach programs are organized in the form of subroutines or subprograms.
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
b) Procedural Programming

Question 7.
…………………. approach of the program is time-consuming.
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
b) Procedural Programming

Question 8.
……………… language is based on procedural programming.
a) FORTRAN
b) COBOL
c) Both A and B
d) C++
Answer:
c) Both A and B

Question 9.
…………….. paradigm consists of multiple modules; each module has a set of functions of related types.
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
a) Modular Programming

Question 10.
In ……………… approach data is hidden under the modules
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
a) Modular Programming

Question 11.
______ language is based on modular programming.
a) Pascal
b) C
c) Both A and B
d) C++
Answer:
c) Both A and B

Question 12.
………………. paradigm emphasizes the data rather than the algorithm.
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
c) Object-Oriented Programming

Question 13.
………………… implements programs using classes and objects.
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
c) Object-Oriented Programming

Question 14.
A …………….. is a construct in C++ which is used to bind data and its associated function together into a single unit.
a) Class
b) Structure
c) Array
d) None of these
Answer:
a) Class

Question 15.
A Class is a construct in C++ which uses the ……………….. concept.
a) Polymorphism
b) Encapsulation
c) Abstraction
d) Inheritance
Answer:
b) Encapsulation

Question 16.
Class is a ……………… data type.
a) User-defined
b) Derived
c) Primitive
d) None of these
Answer:
a) User-defined

Question 17.
…………………. can be defined as a template or blueprint representing a group of objects that share common properties and relationship.
a) Class
b) Structure
c) Array
d) None of these
Answer:
a) Class

Question 18.
……………….. are the basic unit of OOP.
a) Attributes
b) Objects
c) Members
d) None of these
Answer:
b) Objects

Question 19.
The class variables are called……………………
a) Instances
b) Objects
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 20.
An identifiable entity with some characteristics and behaviour is called ………………
a) Instances
b) Objects
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 21.
In ……………… method, programs are designed around the data being operated.
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
c) Object-Oriented Programming

Question 22.
………………… language is based on object-oriented programming.
a) C++, Java
b) VB.Net
c) Python
d) All the above
Answer:
d) All the above

Question 23.
……………… is widely accepted that object-oriented programming is the most important and powerful way of creating software.
a) Modular Programming
b) Procedural Programming
c) Object-Oriented Programming
d) All the above
Answer:
c) Object-Oriented Programming

Question 24.
The Object-Oriented Programming approach mainly encourage ______
a) Modularisation
b) Software re-use
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 25.
…………………….. means the program can be decomposed into modules.
a) Modularisation
b) Software re-use
c) Both A and B
d) None of these
Answer:
a) Modularisation

Question 26.
………………… means, a program can be composed of existing and new modules.
a) Modularisation
b) Software re-use
c) Both A and B
d) None of these
Answer:
b) Software re-use

Question 27.
The main feature of Object-Oriented Programming is ………………….
a) Data Abstraction and Encapsulation
b) Modularity
c) Inheritance and Polymorphism
d) All the above
Answer:
d) All the above

Question 28.
……………………. implements abstraction.
a) Polymorphism
b) Encapsulation
c) Abstraction
d) Inheritance
Answer:
b) Encapsulation

Question 29.
……………….. can be called data binding.
a) Polymorphism
b) Encapsulation
c) Abstraction
d) Inheritance
Answer:
b) Encapsulation

Question 30.
……………………… is the most striking feature of a class,
a) Polymorphism
b) Encapsulation
c) Abstraction
d) Inheritance
Answer:
b) Encapsulation

Question 31.
The encapsulation of data from direct access by the program is called …………………….
a) Data hiding
b) Information hiding
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 32.
…………………… refers to showing only the essential features without revealing background details,
a) Polymorphism
b) Encapsulation
c) Abstraction
d) Inheritance
Answer:
c) Abstraction

Question 33.
The attributes are called ……………………..
a) Data members
b) Methods
c) Member functions
d) Either B or C
Answer:
a) Data members

Question 34.
…………………….. hold information.
a) Data members
b) Methods
c) Member functions
d) Either B or C
Answer:
a) Data members

Question 35.
The functions that operate on data numbers are called …………………..
a) Data members
b) Methods
c) Member functions
d) Either B or C
Answer:
d) Either B or C

Question 36.
………………. is designing a system that is divided into a set of functional units.
a) Polymorphism
b) Modularity
c) Abstraction
d) Inheritance
Answer:
b) Modularity

Question 37.
……………………. is the technique of building new classes from an existing class,
a) Polymorphism
b) Modularity
c) Abstraction
d) Inheritance
Answer:
d) Inheritance

Question 38.
In inheritance, the existing class is called as …………………….. class.
a) Base
b) Derived
c) Abstract
d) None of these
Answer:
a) Base

Question 39.
In inheritance, the newly created class is called as ………………… class.
a) Base
b) Derived
c) Abstract
d) None of these
Answer:
b) Derived

Question 40.
……………… is the ability of a message or function to be displayed in more than one form.
a) Polymorphism
b) Modularity
c) Abstraction
d) Inheritance
Answer:
a) Polymorphism

Question 41.
……………. means, write once and use it multiple times.
a) Re-usability
b) Redundancy
c) Security
d) None of these
Answer:
a) Re-usability

Question 42.
If we need the same functionality in multiple class you will write a common class for the same functionality and inherit that class to subclass is called ……………………
a) Re-usability
b) Redundancy
c) Security
d) None of these
Answer:
b) Redundancy

Question 43.
………………. is a good feature for data redundancy.
a) Polymorphism
b) Modularity
c) Abstraction
d) Inheritance
Answer:
d) Inheritance

Question 44.
…………………… programs are much larger than other programs.
a) Modular
b) Procedural
c) Object-Oriented
d) All the above
Answer:
c) Object-Oriented

Question 45.
………………….. program requires a lot of work to create.
a) Modular
b) Procedural
c) Object-Oriented
d) All the above
Answer:
c) Object-Oriented

Question 46.
……………… programs .are slower than other programs, because of their size.
a) Modular
b) Procedural
c) Object-Oriented
d) All the above
Answer:
c) Object-Oriented

Very Short Answers 2 Marks

Question 1.
Write a note on an object-oriented program.
Answer:
Object-Oriented Programming (OOP) is the term used to describe a programming approach based on classes and objects. The object-oriented paradigm allows us to organize software as a collection of objects that consist of both data and behaviour.

Question 2.
What is modularity?
Answer:
Modularity is designing a system that is divided into a set of functional units (named modules) that can be composed into a larger application.

Question 3.
Define Data binding.
Answer:
Encapsulation is about binding the data variables and functions together in class. It can also be called data binding.

Short Answers (3 Marks)

Question 1.
Write about objects.
Answer:
Objects: Represents data and its associated function together into a single unit. Objects are the basic unit of OOP. Basically, an object is created from a class. They are instances of class also called class variables. An identifiable entity with some characteristics and behaviour is called an object.

Question 2.
What are Encapsulation and data binding?
Answer:
The mechanism by which the data and functions are bound together into a single unit is known as Encapsulation. Encapsulation is the most striking feature of a class. The data is not accessible to the outside world, and only those functions which are wrapped in the class can access it. These functions provide the interface between the object’s data and the program. This encapsulation of data from direct access by the program is called data hiding or information hiding.

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Computer Science Guide Pdf Chapter 12 Arrays and Structures Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Computer Science Solutions Chapter 12 Arrays and Structures

11th Computer Science Guide Arrays and Structures Text Book Questions and Answers

Book Evaluation

Part I

Choose The Correct Answer

Question 1.
which of the following is the collection of variables of the same type that are referenced by a common name ?
a) int
b) float
c) Array
d) class
Answer:
c) Array

Question 2.
Array subscripts is always starts with which number ?
a) -1
b) 0
c) 2
d) 3
Answer:
b) 0

Question 3.
int age[ ]={6,90,20,18,2}; How many elements are there in this array?
a) 2
b) 5
c) 6
d) 4
Answer:
b) 5

Question 4.
cin>>n[3]; To which element does this statement accepts the value?
a) 2
b) 3
c) 4
d) 5
Answer:
c) 4

Question 5.
By default, the string end with which character?
a) \0
b) \t
c) \n
d) \b
Answer:
a) \0

Part – II

Very Short Answers

Question 1.
What is Traversal in an Array?
Answer:
Accessing each element of an array at least once to perform any operation is known as “Traversal”. Displaying all the elements in an array is an example of “traversal”.

Question 2.
What is Strings?
Answer:
A string is defined as a sequence of characters where each character may be a letter,’ number or a symbol.
Every string is terminated by a null (\0) character which must be. appended at the end of the string.

Question 3.
What is the syntax to declare two – dimensional array? ‘
Answer:
The declaration of a 2-D array is
datatype array_name[row – size] [col – size];
In the above declaration, data-type refers to any valid C++ data – type, array _ name refers to the name of the 2 – D array, row – size refers to the number of rows and col-size refers to the number of columns in the 2 – D array.

Part – III

Short Answers

Question 1.
Define an Array. What are the types?
Answer:
An array is a collection of variables of the same type that are referenced by a common name.
There are different types of arrays used in C++. They are:

• One-dimensional arrays
• Two-dimensional arrays
• Multi-dimensional arrays

Question 2.
With note an Array of strings.
Answer:
An array of strings is a two – dimensional character array. The size of the first Index (rows) denotes the number of strings and the size of the second index (columns) denotes the maximum length of each string. Usually, an array of strings are declared in such a way to accommodate the null character at the end of each string. For example, the 2-D array has the declaration:
char name [7][10];
In the above declaration,
No. of rows = 7;
No. of columns = 10;
We can store 7 strings each with a maximum length of 10 characters.

Question 3.
Write a C++ program to accept and print your name?
Answer:
PROGRAM
#include<iostream>
using namespace std;
int main( )
{
char str[100];
cout<< “Enter your name :”;
cin.get(str,100);
cout<< “You name is : ” << str <<endl;
return 0;
}
Output

Part – IV

Explain In Detail

Question 1.
write a c++ program to find the difference between two matrix.
Answer:
PROGRAM
#include<iostream>
#include<conio.h>
using namespace std;
int main( )
{
int row, col, m1[10][10], m2[10][10], sum[10][10];
cout<<“Enter the number of rows : “;
cin>>row;
cout<<“Enter the number of columns :”;
cin>>col;
cout<< “Enter the elements of first matrix: “<<endl;
for (int i = 0;i<row;i++ )
for (int j = 0;j <col;j++ )
cin>>m1[i][j];
cout< < “Enter the elements of second matrix: “<<endl;
for (int i = 0;i<row;i++ )
for (int j = 0;j<col;j++ )
< cin>>m2[i][j];
cout<<“Output: “<<endl;
for (int i = 0;i<row;i++ )
{
for (int j = 0;j<col;j++ )
{
sum[i][j]=m1[i][j] – m2[i][j]); cout<<sum[i][j]<<“”;
}
cout<<endl<<endl;
}
getch( );
return 0;
}
Output

Question 2.
How will you pass two dimensional array to a function explain with example.
Answer:
Passing 2″D array to a function:
C++ program to display values from two dimensional array.
#include<iostream>
using namespace std;
void display (int n[3][2]);
int main( )
{
int num[3][2] = { {3, 4}, {9, 5>, {7, 1} } ;
display(num);
return 0;
}
void display(int n[3][2])
{
cout << “\n Displaying Values” << endl; for (int i=0; i<3; i++)
{
for (int j=0; j<2; j++)
{
cout << n[i][j] << “”;
}
cout << endl << endl;
}
}
Output
Displaying Values
3 4
9 5
7 1
In the above program, the two-dimensional array num is passed to the function display
( ) to produce the results.

11th Computer Science Guide Arrays and Structures Additional Questions and Answers

Choose The Correct Answer (1 Mark)

Question 1.
The size of the array is referred to as its ………………..
(a) dimension
(b) direction
(c) location
(d) space
Answer:
(a) dimension

Question 2.
…………… is an easy way of storing multiple values of the same type referenced by a common name.
a) Variables
b) Literals
c) Array
d) None of these
Answer:
c) Array

Question 3.
Displaying all the elements in an array is an example of ………………..
(a) memory allocation
(b) call by reference
(c) traversal
(d) none of these
Answer:
(c) traversal

Question 4.
A (n) ………………….. is a collection of variables of the same type that are referenced by a common name.
a) Structures
b) Array
c) Unions
d) None of these
Answer:
b) Array

Question 5.
During ……………….. the array of elements cannot be initialized more than its size.
(a) declaration
(b) initialization
(c) assigning
(d) execution
Answer:
(b) initialization

Question 6.
The …………….. of the array is referred to as its dimension.
a) Elements
b) Size
c) Format
d) None of these
Answer:
b) Size

Question 7.
Pass an array to a function in C++, the function needs the array name as ………………..
(a) a function
(b) an argument
(c) global object
(d) string
Answer:
(b) an argument

Question 8.
…………………. is a type of arrays used in C++.
a) One-dimensional array
b) Two-dimensional array
c) Multidimensional array
d) All the above
Answer:
d) All the above

Question 9.
A structure without a name tag is called ………………..
(a) homogenous structure
(b) anonymous structure
(c) array of structure
(d) dynamic memory
Answer:
(b) anonymous structure

Question 10.
A one-dimensional array represents values that are stored in a single …………….
a) Row
b) Column
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 11.
Array size should be specified with …………………
a) square brackets[ ]
b) Parenthesis ( )
c) Curly braces{ }
d) Angle brackets < >
Answer:
a) square brackets[ ]

Question 12.
In an array declaration, ……………… defines how many elements the array will hold.
a) array_name
b) array_size
c) data_type
d) None of these
Answer:
b) array_size

Question 13.
In an array declaration, …………………. declares the basic type of the array, which is the type of each element in the array.
a) array_name
b) array_size
c) data type
d) None of these
Answer:
c) data type

Question 14.
In an array declaration, ……………….. specifies the name with which the array will be referenced
a) array_name
b) array_size
c) data type
d) None of these
Answer:
a) array_name

Question 15.
The array subscript always starts with ………………
a) 0
b) 1
c) -1
d) None of these
Answer:
a) 0

Question 16.
The subscript always is a(n) ………………value.
a) Integer
b) Unsigned integer
c) Signed integer
d) float
Answer:
b) Unsigned integer

Question 17.
In Turbo C++, int data type requires …………….. bytes of memory.
a) 4
b) 8
c) 2
d) 1
Answer:
c) 2

Question 18.
In Dev C++, int data type requires ………………. bytes of memory,
a) 4
b) 8
c) 2
d) 1
Answer:
a) 4

Question 19.
The memory space allocated for an array can be calculated using the -formula.
a) Number of bytes allocated for the type of array + Number of elements
b) Number of bytes allocated for the type of array x Number of elements
c) Number of bytes allocated for the type of array – Number of elements
d) None of these
Answer:
b) Number of bytes allocated for the type of array x Number of elements

Question 20.
An array can be initialized at the time of its ………………
a) Declaration
b) Process
c) Either A or B
d) None of these
Answer:
a) Declaration

Question 21.
Unless an array is initialized, all the array elements contain ……………..values.
a) Null
b) Default
c) Garbage
d) None of these
Answer:
c) Garbage

Question 22.
While declaring and Initializing values In an array, the values should be given within the ……………..
a) square brackets[ ]
b) Parenthesis ()
c) Curly braces{ }
d) Angle brackets < >
Answer:
c) Curly braces{ }

Question 23.
The …………….. of an array may be optional when the array is initialized during declaration.
a) Data type
b) Size
c) Name
d) None of these
Answer:
b) Size

Question 24.
The subscript in the bracket can be a(n) ……………….
a) Variable
b) Constant
c) Expression that evaluates to an integer
d) Either A or B or C
Answer:
d) Either A or B or C

Question 25.
Accessing each element of an array at least once to perform any operation is known as ………………..
a) Traversal
b) Process
c) Reference
d) None of these
Answer:
a) Traversal

Question 26.
…………………. is a process of finding a particular value present in a given set of numbers.
a) Filtering
b) Searching
c) Seeking
d) None of these
Answer:
b) Searching

Question 27.
The ………………. compares each element of the list with the value that has to be searched until all the elements in the array have been traversed and compared.
a) Linear search
b) Sequential search
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 28.
A ……………. is defined as a sequence of characters where each character may be a letter, number, or a symbol.
a) String
b) Character
c) Literal
d) Identifier
Answer:
a) String

Question 29.
In C++, there is no basic data type to represent a …………….
a) String
b) Character
c) Literal
d) float
Answer:
a) String

Question 30.
How much memory required for the following array?
char country[6];
a) 12 bytes
b) 6 bytes
c) 60 Bytes
d) 24 bytes
Answer:
b) 6 bytes

Question 31.
…………….. is a way of initializing the character array:
a) char country[6]={T, ‘N’ ‘D’ ‘I’, ‘A’, ‘\0’};
b) char country[ ]=”INDIA”;
c) char country[ ]={T, ‘N’, ‘D’, T, ‘A’ ‘\0’};
d) Either A or B or C
Answer:
d) Either A or B or C

Question 32.
Which is a correct statement from the following?
a) At the end of the string, a null character is automatically added by the compiler.
b) If the size of the array is not explicitly mentioned, the compiler automatically calculates the size of the array based on the number of elements in the list and allocates space accordingly.
c) In the initialization of the string, if all the characters are not initialized, then the rest of the characters will be filled with NULL.
d) All the above
Answer:
d) All the above

Question 33.
In C++,………………. is used to read a line of text including blank spaces.
a) cin.get( )
b) cin
c) put( )
d) None of these
Answer:
a) cin.get( )

Question 34.
………………. function can read the characters till it encounters a newline character or a delimiter specified by the user.
a) getline( )
b) put
c) puts( )
d) None of these
Answer:
a) getline( )

Question 35.
…………………. arrays are a collection of similar elements where the elements are stored in a certain number of rows and columns.
a) One dimensional
b) Two dimensional
c) Multidimensional
d) All the above
Answer:
b) Two dimensional

Question 36.
In two dimensional arrays, …………………. size is compulsory.
a) Column
b) Row
c) Both A and B
d) None of these
Answer:
a) Column

Question 37.
In two dimensional arrays, …………….. size is optional.
a) Column
b) Row
c) Both A and B
d) None of these
Answer:
b) Row

Question 38.
int A[3][4 j; How many elements are there in the array “A”?
a) 3
b) 4
c) 7
d) 12
Answer:
d) 12

Question 39.
The two-dimensional array uses ………………. index values to access a particular element in it.
a) two
b) one
c) three
d) many
Answer:
a) two

Question 40.
In a two dimensional array, the first index specifies the …………….. value.
a) Column
b) Row
c) Both A and B
d) None of these
Answer:
b) Row

Question 41.
In a two dimensional array, the second index specifies the …………… value.
a) Column
b) Row
c) Both A and B
d) None of these
Answer:
a) Column

Question 42.
The two-dimensional array can be viewed as a …………………
a) List
b) Matrix
c) Linear block
d) None of these
Answer:
b) Matrix

Question 43.
There are …………… types of 2-D array memory representations.
a) two
b) one
c) three
d) many
Answer:
a) two

Question 44.
……………… is a type of 2-D array memory representation.
a) Row-Major order
b) Column-Major order
c) Either A or B
d) None of these
Answer:
c) Either A or B

Question 45.
In row-major order, all the elements are stored ……………… in contiguous memory locations.
a) Column by Column
b) Row by Row
c) Both A and B
d) None of these
Answer:
b) Row by Row

Question 46.
In column-major order, all the elements are stored ………………. in contiguous memory locations.
a) Column by Column
b) Row by Row
c) Both A and B
d) None of these
Answer:
a) Column by Column

Question 47.
An array of strings is a ………………. dimensional character array,
a) Two
b) One
c) Multi
d) None of these
Answer:
a) Two

Question 48.
In a two-dimensional character array, the size of the first index (rows) denotes the ……………….
a) Maximum length of each string
b) Number of strings
c) Maximum characters
d) None of these
Answer:
b) Number of strings

Question 49.
In a two-dimensional character array, the size of the second index (rows) denotes the ……………….
a) Maximum length of each string
b) Number of strings
c) Maximum characters
d) None of these
Answer:
a) Maximum length of each string

Question 50.
char Name[6][10]; How many strings can be stored in the above array?
a) 10
b) 60
c) 6
d) 16
Answer:
c) 6

Question 51.
To pass an array to a function in C++, the function needs the ………….. as an argument,
a) Array name
b) Array type
c) Dimension
d) None of these
Answer:
a) Array name

Very Short Answers (2 Marks)

Question 1.
What is the formula to calculate the memory space allocated for an array?
Answer:
A number of bytes allocated for the type of array x Number of elements.

Question 2.
What are the types of arrays?
Answer:
There are different types of arrays used in C++. They are:

1. One-dimensional arrays
2. Two-dimensional arrays
3. Multi-dimensional arrays

Question 3.
Write about returning structures from functions.
Answer:
A structure can be passed to a function through its object. Therefore, passing a structure to a function or passing a structure object to a function is the same because the structure object represents the structure. Like a normal variable, a structure variable(structure object) can be passed by value or by references/addresses. Similar to built-in data types, structures also can be returned from a function.

Question 4.
Write the syntax and example for one-dimensional declaration and initialization.
Answer:
Syntax:
[size] = {value-1,value-2,………….,value-n};
Example:

Question 5.
What is a global object?
Answer:
Objects declared along with structure definition are called global objects.

Question 6.
Write a note on strings.
Answer:
strings:
A string is defined as a sequence of characters where each character may be a letter, number or symbol. Each element occupies one byte of memory. Every string is terminated by a null C\0′ ASCII code 0) character which must be appended at the end of the string.

Question 7.
Differentiate array and structure.
Answer:
Array:

• An array is a collection of variables of the same data type.
• Array data are accessed using index.
• Array allocates static memory
• Array element access takes lesser time.

Structure:

• A structure is a collection of variables of different data type.
• Structure elements are accessed using operator.
• Structures allocate dynamic memory.
• Structure elements take more time.

Short Answers (3 Marks)

Question 1.
Write about the initialization of 2 – D array.
Answer:
The array can be initialized in more than one way at the time of 2-D array declaration.
For example
int matrix[4][3] = {
{10,20,30},// Initializes row 0
{40,50,60},// Initializes row 1
{70,80,90},// Initializes row 2
{100,110,120}// Initializes row 3
};
int matrix[4][3] = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120};
Array’s row size is optional but column size is compulsory.

Question 2.
What is subscript? Give its rules,
Answer:
subscript:
Each element has a unique index number starting from 0 which is known as a subscript.
Rules for subscript:

• The subscript always starts with 0.
• It should be an unsigned integer value.
• Each element of an array is referred to by its name with a subscript index within the square bracket.

For example:
num[3] refers to the 4th element in the array.

Question 3.
How memory locations are allocated to a one-dimensional array?
Answer:
Memory representation of a one-dimensional array:
The amount of storage required to hold an array is directly related to type and size.
The following figure shows the memory allocation of an array with five elements.

The above figure clearly shows that the array num is an integer array with 5 elements. Here, there is a total of 5 elements in the array, where for each element, 4 bytes in Dev C++ (or)2 bytes in Turbo C++ will be allocated. Totally 20 bytes will be allocated for this array (In Turbo C++ 10 Bytes).

Question 4.
Tabulate the memory requirement of data type in Turbo C++ and Dev C++.
Answer:

Data type	Turbo C++	Dev C++
char	1	1
int	2	4
float	4	4
long	4	4
double	8	8
long double	10	10

Question 5.
Explain character Array (String) creation with syntax and example.
Answer:
To create any kind of array, the size (length) of the array must be known in advance, so that the memory locations can be allocated according to the size of the array. Once an array is created, its length is fixed and cannot be changed during run time, This is shown in the following figure.

Syntax of array declaration is:
char array_name[size];
In the above declaration, the size of the array must be an unsigned integer value.

For example,
char country[6];
Here, the array reserves 6 bytes of memory, for storing’ a seqi characters. The length of the string cannot be more than 5 characters and one location is reserved for the null character at the end.

Question 6.
What is an array of strings?
Answer:
An array of strings is a two – dimensional character array. The size of the first index (rows) denotes the number of strings and the size of the second index (columns) denotes the maximum length of each string. Usually, an array of strings are declared in such a way to accommodate the null character at the end of each string. For example, the 2 – D array has the declaration: char Name[6][10];
In the above declaration, the 2 – D array has two indices which refer to the row size and column size, that is 6 refers to the number of rows, and 10 refers to the number of columns.

Question 7.
Write note on getline( ) function.
Answer:
In C++, getline( ) is also used to read a line . of text from the input stream. It can read the characters tilt it encounters a newline character or a delimiter specifier’ by the user. This function is available in the header.

Question 8.
How memory represented for a 2-D array?
Answer:
There are two types of 2-D array memory representations. They are:

• Row Major order
• Column Major order

For example:
int A[4][3]={ { 8,6,5}, { 2,1,9}, {3,6,4}, {4,3,2} };
Row Major order:
In row-major order, all the elements are stored row by row in continuous memory locations, that is, ail the elements in first row, then in the second row and soon. The memory representation of row-major order is as shown below.

Question 9.
How 2-D character array initialized and stored in memory? Explain.
Answer:
2D char array initialization:

For example:
char Name[6][10] = {“Mr. Bean’; “Mr.Bush”
“Nicole”, “Kidman” “Arnold”, “Jodie”};
In the above’ example, the 2-D array is initialized with 6 strings, where the string is a maximum of 9 characters long since the last character is null. The memory arrangement of a 2-D array is shown below and ail the strings are stored in continuous locations.

Question 10.
What is called nested structure? Give example.
Answer:
The structure declared within another structure is called a nested structure. Nested structures act as members of another structure and the members of the child structure can be accessed as parent structure name. Child structure name. Member name, struct dob
{
int date;
char month[3];
int year;
} ;
Values can be assigned to this structure as follows.
dob = {25, “DEC”, 2017}

Question 11.
Write a program to pass an array as an argument to a function.
Answer:
In C++, arrays can be passed to a function as an argument.
To pass an array to a function in C++, the function needs the array name as an argument.
C++ program-to display marks of 5 students (one-dimensional array)
#indude<iostream>
using namespace std;
void display (int m[5]);
int main( )
{
int marks[5]={88, 76, 90, 61, 69};
display(marks);
return 0;
}
void’ display (int m[5])
{
cout << “\n. Display Marks: ” << end!; for (int i=0; i<5; i++)
{
cout <-< “Student” << i+1 << ” << m[i]<<endl;
}
}
Output
Display Marks:
Student 1: 88
Student 2: 76
Student 3: 90
Student 4: 61
Student 5: 69

Question 12.
Write a C++ program to pass a 2-D array to a function.
Answer:
C++ program to display values from two dimensional array:
#include<iostream>
using namespace std;
void display (int n[3][2]);
int main( )
{
int num[3][2] = { {3, 4}, (9, 5}, {7,1} };
display(num);
return 0; ‘
}
void display(int n[3][2])
{
cout << “\n Displaying Values” << endl;
for (int i=0; i<3; i++)
{
for (int j=0; j<2; j++)
{
cout << n[i][j] << ”
}
cout << endl << endl;
}
}
Output
Displaying Values
3 4
9 5
7 1

Question 13.
Write a user-defined function to return the structure after accepting value through the keyboard. The structure definition is as follows: struct Item{int item no; float price;};
Answer:
item accept (item i)
{

cout << “\n Enter the Item No:”; cin >> i.no;
cout << “\n Enter the Item Price:”; cin >> i.price;
return i;

}

Explain in Detail (5 Marks)

Question 1.
How will you search an element in a one-dimensional array? Explain linear search.
Answer:
Searching in a one-dimensional array:
Searching is a process of finding a particular value present in a given set of numbers. The linear search or sequential search compares each element of the list with the value that has to be searched until all the elements in the array have been traversed and compared.

Program for Linear Search
#include<iostream>
using namespace std;
int Search(int arr[ ], int size, int value)
{
for (int i=0; <size; i++)
{
if (arr[i] == value)
return i; // return index value
}
return -1;
}
int main( )
{
int num[10], val, id;
for (int i=0; i< 10; i++) .
{
cout<<“\n Enter value” << i+1 <<“=”;
cin>>num[i];
}
cout<< “\n Enter a value to be searched: “;
cin>>val;
id=Search(num,10,val);
if(id==-1) .
cout<< “\n Given value is not found in the array..”;
else
cout<< “\n The value is found at the position” << id+1;
return 0;
}
The above program reads an array and prompts for the values to be searched. It calls the Search() function which receives array, size and value to be searched as parameters. If the value is found, then it returns the array index to the called statement; otherwise, it returns -1.

Question 2.
Explain two-dimensional array with syntax and example.
Answer:
Two-dimensional array:
Two-dimensional (2D) arrays are collections of similar elements where the elements are stored in a certain number of rows and columns. An example m x n matrix where m denotes the number of rows and n denotes the number of columns is shown in the following figure, int arr[3][3];
2D array conceptual memory representation

The array arr can be conceptually viewed in matrix form with 3 rows and columns. point to be noted here is since the subscript starts with 0 arr [0][0] represents the first element.

The syntax for declaration of a 2-D array is:
data-type array_name[row-size][col-size];
In the above declaration, data-type refers to any valid C++ data-type, array_name refers to the name of the 2-D array, row-size refers to the number of rows and col-size refers to the number of columns in the 2-D array.

For example:
int A[3][4];
In the above example, A is a 2-D array, 3 denotes the number of rows and 4 denotes the number of columns. This array can hold a maximum of 12 elements.

Case Study

Question (1)
Write a program to accept the marks of 10 students and find the average, maximum and minimum marks.
Answer:
PROGRAM
#include<iostream>
using namespace std;
int main( )
{
int marks[10], sum=0,max,min;
float avg;
cout<< “\n Enter Mark 1” << “=”;
cin>> marks[0];
max=marks[0];
min=marks[0];
for(int i=1; i< 10; i++)
{
cout<< “\n Enter Mark” << i+1 << “=”;
cin>> marks[i];
sum=sum+marks[i];
if (marks[i]>max)
max = marks[i];
if (marks[i]<min)
min = marks[i];
}
avg=sum/10.0;
cout<< “\n The Total Marks: ” << sum;
cout<< “\n The Average Mark: ” <<avg;
cout<< “\n The Maximum Mark: ” <<max;
cout<< “\n The Minimum Mark: ” <<min;
}
Output

Question (2)
Write a program to accept rainfall recorded in four metropolitan cities of India and find the city that has the highest and lowest rainfall.
Answer:
PROGRAM
#include<iostream>
#include<string.h>
using namespace std;
int main( )
{
int rate[10],min,n;
char shop[5][20];
char minshop[20];
cout<<“\nHow many Shops
cin>>n;
for(int i=0;i<n;i++)
{
cout<<“\nEnter Name of the Shop “<<i+1<<” :”;
cin> >shop[i];
cout<<“\nEnter price of Product-X at “<<shop[i]<<” :”;
cin>>rate[i];
}
min=rate[0];
strcpy(minshop,shop[0]);
for(int i=l;i<n;i++)
{
if (rate[i]<min)
{
min = rate[i];
strcpy(minshop,shop[i]);
}
}
cout< < “\n The Lowest cost of the Proudct=X at the” “<<minshop <<“is”<<min;
}
Output

Question (3)
Survey your neighboring shops and find the price of any particular product of interest and suggest where to buy the product at the lowest cost.
Answer:
PROGRAM
#include<iostream>
#include<string.h>
using namespace std;
int main( )
{
int rate[10],min,n;
char shop[5][20];
char minshop[20];
cout<<“\nHow many Shops “;
cin>>n;
for(int i=0;i<n;i++)
{
cout<<“\nEnter Name of the Shop “<<i+l<<” :”;
cin>>shop[i];
cout<<“\nEnter price of Product-X at “<<shop[i]<<“:”;
cin> >rate[i];
}
min=rate[0];
strcpy(nninshop,shop[0]);
for(int i=l;i<n;i++)
{
if (rate[i]<min)
{
min = rate[i];
strcpy(minshop,shop[i]);
}
}
cout< < “\n The Lowest cost of the Proudct=X at the ” <<minshop <<“is”<<min;
}
Output

STRUCTURES

Book Evaluation

Part -I

Choose The Correct Answer

Question 1.
The data elements in the structure are also known as ……………..
a) objects
b) members
c) data
d) records
Answer:
b) members

Question 2.
Structure definition is terminated by ……………..
a) :
b) }
c) ;
d) ::
Answer:
c) ;

Question 3.
What will happen when the structure is declared?
a) it will not allocate any memory
b) it will allocate the memory
c) it will be declared and initialized
d) it will be only declared
Answer:
b) it will allocate the memory

Question 4.
What is the out of this program?
#include<iostream>
#include<string.h>
using namespace std;
int main( )
{
struct student
{
int n;
char name[10];
};
students;
s.n = 123;
183
strcpy(s.name, “Balu”);
cout<<s.n;
co
ut<< s.name <<endl;
return 0;
}
a) 123Balu
b) BaluBalu
c) Balul23
d) 123 Balu
Answer:
a) 123Balu

Question 5.
A structure declaration is given below.
struct Time
{
int hours;
int minutes;
int seconds;
}t;
Using the above declaration which of the following refers to seconds.
a) Time.seconds
b) Time::seconds
c) seconds
d) t. seconds
Answer:
d) t. seconds

Question 6.
What will be the output of this program?
#include <iostream>
using namespace std;
struct ShoeType
{
string name; double price;
>; , ‘ ‘
int main()
184 {
ShoeType shoe1, shoe2;
shoe1.name = “Adidas”;
shoe1.price = 9.99;
cout<< shoe1.name<< ” #. “<< shoe1.
price<<endl;
shoe2 = shoe1;
shoe2.price = shoe2.price / 9;
cout<< shoe2.name<< ” # “<< shoe2.price;
return 0;

a) Adidas # 9.99 Adidas #1.11	b) Adidas # 9.99 Adidas # 9.11
c) Adidas # 9.99 Adidas # 11.11	d) Adidas #9.11 Adidas # 11.11

Answer:
a) Adidas # 9.99 Adidas #1.11

Question 7.
Which of the following is a properly defined structure?
a) struct {int num;}
b) struct sum {int num;}
c) struct sum int sum;
d) struct sum {int num;};
Answer:
d) struct sum {int num;};

Question 8.
A structure declaration is given below.
struct employee
{
int empno;
char ename[10];
} e[5];
Using the above declaration which of the following statement is correct.
a) cout<<e[0].empno<<e[0].ename;
b) cout<<e[0].empno<<ename;
c) cout< <e[0]->empno< <e[0]->ename;
d) cout<<e.empno<<e.ename;
Answer:
a) cout<<e[0].empno<<e[0].ename;

Question 9.
Which of the following cannot be a structure member?
a) Another structure
b) Function
c) Array
d) variable of double datatype
Answer:
b) Function

Question 10.
When accessing a structure member, the identifier to the left of the dot operator is the name of
a) structure variable
b) structure tag
c) structure member
d) structure-function
Answer:
a) structure variable

Part – II

Very Short Answers

Question 1.
Define structure. What is its use?
Answer:
Definition:
The structure is user-defined which has the combination of data items with different data types. This allows to a group of variables of mixed data types together into a single unit.
Use: The structure provides a facility to store different data types as a part of the same logical element in one memory chunk adjacent to each other.

Question 2.
To store 100 integer numbers which of the following is good to use?
Answer:
Array or Structure State the reason.
In any situation when more than one variable is required to represent objects of uniform data types, an array can be used. If the elements are of different data types, then the array cannot support them.
The structure provides a facility to store different data types as a part of the same logical element in one memory chunk adjacent to each other. So, to store 100 integer numbers Array is good.

Question 3.
What is the error in the following structure definition.
Answer:
struct employee {inteno; charename[20]; char dept;}
Employee e1,e2;

Error:
In the above code objects for employee strcture is created at the end of structure definition. So,structure name is not needed. It may written as:
struct employee
{
int eno;
char ename[20];
char dept;
}e1,e2;

Question 4.
Write a structure definition for the structure student containing exam no, name and an array for storing five subject marks.
Answer:
Structure definition:
struct student
{
int examno;
char sname[30];
int mark [5];
};

Question 5.
Why for passing a structure to a function call by reference is advisable to us?
Answer:
In call by reference, any change made to the contents of structure variable inside the function are reflected back to the calling function. Otherwise changes in the structure content within the function will not implement in the structure content.

Question 6.
What is the size of the following highlighted variable in terms of byte if it is compiled in dev C++
Answer:
struct A{ float f[3]; char ch[5];long double d;>;
struct B{ A a; int arr[2][3];}b[3]
struct A {float f[3]; char ch[5]; long double d;>;
Memory requirements (Using Dev C++):

Variable	Memory requirement
float f(3);	12 Bytes
char ch[5];   ,	5 Bytes
double d;	8 Bytes

Using Turbo C++ also the same memory is needed. (Only int data type requirement is differ. Here no int members. So, no change in the requirement.)
struct B { A a; int arr[2][3];}b[3];
Memory requirements (Using Dev C++):

Variable	Memory requirement
A a; (Which is a structure variable)	25 Bytes
int arr[2][3];	24 Bytes
b[3] which is a structure variable of structure B	49 Bytes for each element of b. So, Total requirement of b[3] is 147 Bytes.

Memory requirements (Using Turbo C++):

Variable	Memory requirement
A a; (Which is a structure variable)	25 Bytes
int arr[2][3];	12 Bytes
b[3] which is a structure variable of structure B	37 Bytes for each element of b. So, Total requirement of b[3] is 111 Bytes.

Question 7.
Is the following snippet is fully correct. If not identify the error.
Answer:
struct sum1{ int n1,n2;}s1;
struct sum2{int n1,n2}s2;
cin>>s1.n1>>s1.n2;
s2=s1;
No. It is not fully correct. The following errors are there.
Errors:

Statement	Error
struct sum1 {int n1,n2;}sl;	No Error
struct sum2 {int n1,n2}s2;	Semicolon missing at the end of declaration statement;
cin>>s1.n1>>s1. n2;	No Error
s2-s1;	Objects of different structures can not be directly copied.

Question 8.
Differentiate array and structure.
Answer:
In any situation when more than one variable is required to represent objects of uniform data¬types, array can be used. If the elements are of different data types, then array cannot support. If more than one variable is used, they can be stored in memory but not in adjacent locations. It increases the time consumption while searching.

The structure provides a facility to store different data types as a part of the same logical element in one memory chunk adjacent to each other.

Question 9.
What are the different ways to initialize the structure members?
Answer:
Values can be assigned to structure elements similar to assigning values to variables.
Example:
Consider the following structure: struct Student
{
long int rollno;
int age;
float weight;
}
balu ;
We can initialize as given below:
balu.rollno= 702016;
balu. age=18; ‘
balu.weight= 48.5;
Also, values can be assigned directly as similar to assigning values to Arrays.
balu={702016, 18, 48.5};

Question 10.
What is wrong with the following C++ declarations?
Answer:
A. struct point ( double x, y)
B. struct point { double x, double y >;
C. struct point { double x; double y >
D. struct point { double x; double y; };
E. struct point { double x; double y; >

Errors:
A. struct point (double x, y)
Structure definition must be terminated with;. It is missing. Members must be enclosed in { }. So it may be written as
struct point { double x, y };

B. struct point {double x, double y>;
Structure member declaration must be terminated with; It is missing. So, it may corrected as
struct point {double x; double y;>; or struct point {double x, y;>;

C. struct point {double x; double y>
Structure member declaration and definition must be terminated with ; It is missing. So, it may corrected as
struct point {double x; double y;>; or
struct point { double x, y; >;

D. struct point {double x; double y;};,
No error .
E. struct point {double x; double y;>
– Structure definition must be terminated with ; it is missing. So, it may be corrected as
struct point {double x; double y;>;

Part – III

Short Answers

Question 1.
How will you pass a structure to a function ?
Answer:
A structure variable can be passed to a function in a similar way of passing any argument that is of built-in data type,

1. If the structure itself is an argument, then it is called “call by value”.
2. If the reference of the structure is passed as an argument then it is called, “call by reference”.

Call by value
When a structure is passed as argument to a function using call by value method,any change made to the contents of the structure variable inside the function to which it is passed do not affect the structure variable used as an argument.

Call by reference
In this method of passing the structures to functions, the address of a structure variable / object is passed to the function using address of(&) operator. So any change made to the contents of structure variable inside the function are reflected back to the calling function.

Question 2.
The following code sums up the total of all students name starting with ‘S’ and display it. Fill in the blanks with required statements.
Answer:
struct student {int exam no, lang, eng, phy, che, mat, esc, total; char name[15];>;
int main( )
{
student s[20];
for(int i=0;i<20;i++)
{
…………………. //accept student details
}
for(int i=0;i<20;i++)
{
……………. //check for name starts with’ letter “S”
…………….. // display the detail of the checked name
}
return 0;
}
MODIFIED PROGRAM
using namespace std;
#include<iostream>
struct student
{
int exam_.no,lang,eng,phy,che,mat,esc,total; char name[15];
};
int main( )
{
student s[20];
for(int i=0;i<20;i++)
{
//accept student details
cout<<“\nEnter student name”;
cin>>s[i].name;
cout<<“\nEnter student exam number”;
cin>>s[i].exam_no;
cout<<“\nEnter Languge Mark”;
cin>>s[i].lang;
cout<<“\nEnter Engjish Mark”;
cin>>s[i].eng;
cout<<“\nEnter Physics Mark”;
cin>>s[i].phy;
cout<<“\nEnter Chemistry Mark”;
cin>>s[i].che;
cout<<“\nEnter Maths Mark”;
cin>>s[i].mat;
cout<<“\nEnter Computer Science Mark”;
cin>>s[i].csc;
s[i].total = s[i].lang + s[i].eng + s[i]. phy+s[i].che+s[i].mat+s[i]. csc;
}
cout<<“\nDetails of student name starts with letter S “<<endl;
for(int i=0;i<20;i++)
{
//check for name starts with letter “S” if(s[i].name[0] == ‘S’)
{
// display the detail of the checked name

cout<<“\nName : “<<s[i].
name<<“Total Mark”<<s[i].
total <<endl;
}
}
return 0;
}
Output

Question 3.
What is called nested structure. Give example
Answer:
The structure declared- within another structure is called a nested structure.
Example:
struct Student
{
int age;
float height, weight;
struct dob
{
int date;
char month[4];
int year;
};
}mahesh;
The nested structures act as members of another structure and the members of the child structure can be accessed as parent structure name. Child structure name. Member name.
Example:
mahesh. dob. date
Here

• mahesh is a parent structure name.
• dob is a child structure name
• date is a member of child structure

Question 4.
Rewrite the following program after removing the syntactical error(s), if any.
Answer:
Underline each correction.
struct movie
{
charm_name[10];
charm-Lang[10];
float ticket cost =50;};
Movie;
void main( )
{
gets(m_name);
cin>>m-lang;
return 0; ,
}
MODIFIED PROGRAM
PROGRAM (USING DEV C++)
#include<iostream>
#include<conio.h>
#include<stdio.h>
struct movie
{
char m_name[10];
char m_lang[10];
float ticket_cost;
} Movie;
int main( )
{
std::cout<<“\nEnter Move! Name ;
gets(Movie.m_name);
std::cout<<:”\nEnter Movie Language ,:
std: :cin>>Movie.m -lang;
std::cout<<“\nEnter Ticket Cost: “;
std::cin>>Movie.ticket_cost;
std::cout<<“\nMovie name is : “<
std::cout< <“\nMovie Language is : “<<Movie.m-lang;
std::cout<<“\nTicket cost is : “<<Movie.ticket_cost;
}
Output

Question 5.
What ¡s the difference among the following two programs?
a) #include<iostream.h>
struct point
{
double x;
double y;
};
int main()
{
struct point test;
testx = .25; test.y = .75;
cout< <test.x< ctest.y;
return 0;
}
b) #include
struct .
{
double x;
double y;
} Point;
int main(void)
{
Point test={.25,.75>;
return 0;
}
Answer:
The method of structure initialisation is different.

Question 6.
How to access members of a structure? Give f example.
Answer:
Once the two objects of student structure type are declared, their members can be accessed directly. The syntax for that is using a dot (.) between the object name and the member name.
Syntax is :
Object name. Member

For example:
struct Student
{
longrollno;
int age;
float weight;
}balu, frank;
The elements of the structure Student can be accessed as follows: balu.rollno balu.age balu. weight frank, rollno frank.age frank.weight
balu.rollno
balu.age
balu.weight
frank.rollno
frank.age
frank.weight

Question 7.
Write the syntax and an example for structure.
Answer:
Structure is declared using the keyword ‘struct’. The syntax of creating a structure is given below.
struct structure_name
{
type member_name1;
type member_name2;
} reference_name;
An optional field reference_name can be used to declare objects of the structure type directly.

Example:
struct Student
{
longrollno;
int age;
float weight;
}balu, frank;

Question 8.
For the following structure, definition writes the user-defined function to accept data through the keyboard.
struct date
{
int dd,mm,yy
};
struct item
{
int item id;
char name[10];
float price;
date date_manif;
}
Answer:
USER DEFINED FUNCTION
item accept( )
{
item obj;
cout<<“\n Enter Item Id “;
cin> > obj. item id;
cout<<“\nEnter Name “;
cin>obj.name;
cout<<“\nEnter Price “;
cin>>obj.price;
cout<<“\nEnter Date: date, month and year
cin>>obj.date_manif.dd >> obj.date_manif. mm >> obj.date_manif.yy;
return(obj);
}

Question 9.
What is called an anonymous structure? Give an example.
Answer:
A structure without a name/tag is called anonymous structure, struct
{
long rollno;
int age;
float weight;
} student;
The student can be referred to as a reference name to the above structure and the elements can be accessed like
student, roll no
student.age and
student.weight.

Question 10.
Write a user-defined function to return the structure after accepting value through the keyboard. The structure definition is as follows:
struct Item{int item no;float price;};
Answer:
USER DEFINED FUNCTION
Item accept( )
{
Item obj; ,
cout<<‘AnEnter Item Number and Price “; cin>>obj.item_no>>obj, price.
return(obj);
}

Part-IV

Explain in Detail

Question 1.
Explain the array of structures with examples.
Answer:
A class may contain many students. So, the definition of structure for one student can also be extended to all the students. If the class has 20 students, then 20 individual structures are required. For this purpose, an array of structures can be used.
An array of structures is declared in the same way as declaring an array with built-in data types like int or char.
The following program reads the details of 20 students and prints the same.
#include<iostream>
using namespace std;
struct Student
{
int age;
float height, weight;
char name[30];
};
void main()
{
Student std[20];
int i;
cout<< ” Enter the details for 20 students”<<endl;
for(i=0;i<20;i++)
{
cout<< ” Enter the details of student”<<i+1<<endl;
cout<< ” Enter the age:”<<endl; cin>>std[i].age;
cout<< “Enter the height:”<<endl; cin>>std[i].height;
cout<< “Enter the weight:”<<endl; cin>>std[i].weight;
}
cout<< “The values entered for Age, height and weight are”<<endl;
for(i=0;i<20;i++)
cout<< “Student “<<i+l<< “\t”< <std[i]. age<< “\t”<<std[i].height<< “\t”<<std[i]. weight;
}
Output
Enter the details of 20 students
Enter the details for student1
Enter the age:
18
Enter the height:
160.5
Enter the weight:
46.5
Enter the details for student2
Enter the age:
18
Enter the height:
164.5
Enter the weight:
61.5
………………………………….
…………………………
The values entered for Age, height and weight are
Student 1 18 160.5 46.5
Student 2 18 164.5 61.5
………………………

Question 2.
Explain call by value with respect to structure.
Answer:
A structure variable can be passed to a function in a similar way of passing any argument that is of built-in data type. If the structure itself is an argument, then it is called “call by value”.

Call by value
When a structure is passed as argument to a function using call by value method,any change made to the contents of the structure variable inside the function to which it is passed do not affect the structure variable used as an argument.
Example:
#include<iostream>
using namespace std;
struct Employee
{
char name[50]; ,
int age;
float salary;
};
void printData(Employee); // Function declaration
int main( )
{
Employee p;
cout<< “Enter Full name: “;
cin>>p.name;
cout<< “Enter age: “;
cin>>p.age;
cout<< “Enter salary: “;
cin>>p.salary;
// Function call with structure variable as an argument
printData(p);
return 0;
}
void printData(Employee q)
{
cout<< “\nDisplaying Information.” <<endl;
cout<< “Name: ” << q.name <<endl;
cout<<“Age: ” <<q.age<<endl;
cout<< “Salary:” <<q.salary;
}
Output
Enter Full name: Kumar
Enter age: 55
Enter salary: 34233.4
Displaying Information.
Name: Kumar
Age: 55
Salary: 34233.4
In the above example, a structure named Employee is declared and used. The values that are entered into the structure are name, age and salary of a Employee are displayed using a function named printData( ).

Question 3.
How call by reference is used to pass structure to a function .Give an Example
Answer:
Call by reference
In this method of passing the structures to functions ,the address of a structure variable / object is passed to the function using address of(&) operator. So any change made to the contents of structure variable inside the function are reflected back to the calling function
Example:
#include<iostream>
using namespace std;
struct Employee
{
char name[50];
int age;
float salary;
};
void readData(Employee &);
void printData(Employee);
int main()
{
Employee p;
readData(p);
printData(p);
return 0;
}
void readData(Employee &p)
{
cout<< “Enter Full name: “;
cin.get(p.name, 50);
cout<< “Enter age:
cin>>p.age; ,
cout<< “Enter salary:
cin>>p. salary;
}
void printData(Employee p)
{
cout<< “\nDisplaying Information.” <<endl;
cout<< “Name: ” << p.name <<endl;
cout<<“Age:” <<p.age<<endl;
cout<< “Salary:” <<p.salary;
}
Output
Enter Full name: Kumar
Enter age: 55
Enter salary: 34233.4
Displaying Information.
Name: Kumar
Age: 55
Salary: 34233.4
Structures are usually passed by reference method because it saves the memory space and executes faster.

Question 4.
Write a C++ program to add two distances using the following structure definition
Answer:
struct Distance
{
int feet;
float inch;
}d1, d2, sum;
PROGRAM
#include<iostream>
using namespace std;
struct Distance
{
int feet;
float inch;
} d1, d2, sum;
int main( )
{
cout<<“\nEnter distance 1: feet and inch : “;
cin>>d1.feet>>d1.inch;
cout<<“\nEnter distance 2: feet and inch :
cin>>d2.feet>>d2.inch;
sum.feet = d1.feet + d2.feet;
sum.inch =(d1.inch + d2.inch) – (int) (d1.inch + d2,inch) / 12 * 12;
sum.feet = sum.feet + (d1.inch + d2.inch)/12;
cout<<“\nDitance 1: Feet = “<<d1.feet<<”
Inch = “<<d1.inch;
cout<<“\nDitance 2: Feet = “<<d2.feet<<”
Inch = “<<d2.inch;
cout<<“\nSum of Distance 1 and 2 : Feet = “<<sum.feet<<” Inch = “<<sum.inch;
}
Output

Question 5.
Write a C++ Program to Add two Complex Numbers by Passing Structure to a Function for the following structure definition
Answer:
struct complex
{
float real;
float imag;
};
The prototype of the function is complex add Complex Numbers(complex, complex);
PROGRAM
#include<iostream>
using namespace std;
struct complex
{
float real;
float imag;
};
complex add Complex Numbers (complex obj1,complex obj2)
{
complex obj3;
obj3.real = obj1.reai+obj2,real;
obj3.imag = obj1.imag + obj2.imag;
return(obj3);
}
int main( )
{
complex c1,c2,c3;
cout<<“\nEnter First complex number real and imaginary :”;
cin>>c1,real>>c1.imag;
cout<<“\nEnter Second complex number real and imaginary :”;
cin>>c2.real>>c2.imag;
c3 = addComplexNumbers(c1,c2);
cout<<“\nFirst Complex Number is : “< }
Output

Question 6.
WrIte a C++ Program to declare a structure book containing name and author as character array of 20 elements each and price as Integer. Declare an array of book. Accept the name, author, price detail for each book. Define a user defined function to display the book details and calculate the total price. Return total price to the calling function.
Answer:
PROGRAM
using namespace std;
#include<iostream>
#include<iomanip>
#include<istdio.h>
struct book
{
char bname[20],author[20];
int price;
};
int display(book x[5])
{
int total;
for(int i=0;i<5;i++)
{
total = total + x[i].price;
cout<<“\nBook name : “<<x[i].
bname;
cout<<“\nAuthor name : “<<x[i].
author;
cout<<“\nPrice of the book: “<<x[i].
price;
}
return(total);C++C
}
int main( )
{
book. b[5];
for(int i=0;i<5;i++)
{
cout<<“\nEnter Book name “;
cin>>b[i].bname;
cout<<“\nEnter Author name “;
cin>>b[i].author;
cout<<“\nEnter Book Price “;
cin > > b[i]. price;
}
cout<<“\nDetails of Books”<<endl;
cout<<“\nTotal cost of the book is : Rs.”<<display(b);
}
Output

Question 7.
Write a C++ program to declare and accept an array of professors. Display the details of the department=”COMP.SCI” and the name of the professors start with ‘A’. The structure “college” should contain the following members.
prof-id as integer ,
name and Department as character array
Answer:
PROGRAM
using namespace std;
#include<iostream>
#include<iomanip>
#include<string.h>
struct college .
{
char pname[20],department[20]; int prof-id;
};
void display(college x[5])
{
for(int i=0;i<5;i++)
{
if((strcmp(x[i]. department,”COMP. SCI”)==0) && x[i].pname[0]==’A’)
cout<<x[i].pname«endl;
}
return;
}
int main( )
{
college c[5];
for(int i=0;i <5;i++)
{
cout<<“\nEnter Professor Name “;
cin>>c[i].pname; ,
cout<<“\nEnter Department Name “;
cin> >c[i] .department;
cout< <“\nEnter Professor Id
cin>>c[i].prof-id;
}
cout<<“\nDetails of Comp. Sci. . Dept, Professors whose name starts. with A “<<endl; . display(c);
}
Output

Question 8.
Write the output of the following C++ program
Answer:
#incluçle<iostream>
#include<stdio>
#include<string>
#include<conio>
using namespace std;
struct books
{
char name[20), author[20];
} a[50];
int main ( )
{
clrscr( );
cout<< “Details of Book No ” << 1 << “\n”;
cout<< “———————\n”;
cout<< ‘Book Name :”<<strcpy(a[0].
name,”Programming “)<<endl;
cout<< “Book Author :”<<strcpy(a[0].
author,”Dromy”)<<endl;
cout<< “\nDetails of Book No ” << 2 <<”\n”;
cout<< ” ——————- \n”;
cout<<- “Book Name :”<<strcpy(a[l].
name,”C++programming” )<<endl;
cout<< “Book Author :”<<strcpy(a[l].
author,”BjarneStroustrup “)< <endl;
cout<<“\n\n”;
cout<< “======================
============================
\n”; ‘
cout<< ” S.No\t| Book Name\t|author\n”;
cout<< “=======================
=============================
for (int i = 0; i < 2; i++)
{
cout<< “\n ” << i + 1 << “\t|” << a[i].name << “\t| ” << a[i],author;
}
cout<< “\n=========-==========
===========================
==”;
return 0;
}
Output

Question 9.
Write the output of the following C++ program
Answer:
#include<iostream>
#include<string>
using namespace std;
struct student
{
introll_no;
char name[10];
long phone_number;
};
int main() .
{
student p1 = {1,”Brown”,123443};
student p2, p3;
p2.roll_no = 2;
strcpy(p2.name,”Sam”);
p2.phone_number = 1234567822;
p3.roll_no = 3;
strcpy(p3.name,”Addy”);
p3.phone_number = 1234567844;
cout<< “First Student” <<endl;
cout<< “roll no : ” << p1.roll_no <<endl;
cout<< “name : ” << p1.name <<endl;
cout<< “phone no ; ” << p1.phone_number <<endl;
cout<< “Second Student” <<endl;
cout<< “roll no : ” << p2.roll_no <<endl;
cout<< “name : ” << p2.name <<endl;
cout<< “phone no : ” << p2.phone_number <<endl;
cout<< “Third Student” <<endl;
cout<< “roll no : ” << p3.roll_no <<endl;
cout<< “name : ” << p3.name <<endl;
cout<< “phone no : ” << p3.phone_number <<endl;
return0;
}
Output

Question 10.
Debug the error in the following program.
Answer:



MODIFIED PROGRAM
#include<iostream.h>
struct PersonRec
{
char lastName[10];
char firstName[10];
int age;
}
Person Rec PeopleArrayType[ 10];
void LoadArray(PeopleRec peop[10]);
void main( )
{
PersonRec people [10];
for (i = 0; i < 10; i++)
{
cout< < people[i].firstName< < ” <<peopie[i].lastName <<setw(10) <<people[i].age;
}
}
LoadArray(PersonRec peop[10])
{
for (int i = 0; i < 10; i++)
{
cout<< “Enter first name: “;
cin<<peop[i].firstName;
cout<< “Enter last name: “;
cin>>peop[i].lastName;
cout<< “Enter age: “;
cin>> peop[i].age;←
}

11th Computer Science Guide Arrays and Structures Additional Questions and Answers

Choose The Correct Answer 1 mark

Question 1.
…………….. is a user-defined which has the combination of data items with different data types.
a) Structure
b) Class
c) Union
d) Array
Answer:
a) Structure

Question 2.
…………………. allows to group of variables of mixed data types together into a single unit.
a) Structure
b) Class
c) Union
d) Array
Answer:
a) Structure

Question 3.
If the elements are of different data types,then ……………… cannot support.
a) Structure
b) Class
c) Union
d) Array
Answer:
d) Array

Question 4.
Structure is declared using the keyword …………………
a) Structure
b) struct
c) Stru
d) STRUCT
Answer:
b) struct

Question 5.
Identify the structure name from the following; struct Student balu;
a) balu
b) struct
c) Student
d) None of these
Answer:
c) Student

Question 6.
Identify the structure variable (object) from the following: struct Student balu;
a) balu
b) struct
c) Student
d) None of these
Answer:
a) balu

Question 7.
How much of memory is required for the object of the following structure in Dev C++.
struct Student
{
long rollno;
int age;
float weight;
}balu, frank;
a) 12 Bytes
b) 8 Bytes
c) 10 Bytes
d) None of these
Answer:
a) 12 Bytes

Question 8.
How much of memory is required for the object of the following structure in Turbo C++.
struct Student
{
long rollno;
int age;
float weight;
}balu, frank;
a) 12 Bytes
b) 8 Bytes
c) 10 Bytes
d) None of these
Answer:
c) 10 Bytes

Question 9.
If the members are pointer types then ……………….. is used to access the structure members.
a) →
b) ←
c) .(dot)
d) None of these
Answer:
a) →

Question 10.
A structure without a …………….. is called an anonymous structure.
a) Name
b) Tag
c) Name/Tag
d) None of these
Answer:
c) Name/Tag

Question 11.
…………………… operator is used to accessing structure member.
a) ::
b) @
c) .(dot)
d) $
Answer:
c) .(dot)

Question 12.
The structure declared within another structure is called a …………….. structure.
a) Nested
b) Group
c) Block
d) None of these
Answer:
a) Nested

Question 13.
……………. structures act as members of another structure.
a) Nested
b) Group
c) Block
d) None of these
Answer:
a) Nested

Question 14.
The members of the child structure can be accessed as …………………….
a) Child structure name. Parent structure name. Member name
a) Parent structure name. Child structure name. Member name
a) Parent structure name. Member name. Child structure name
a) Member name. Parent structure name. Child structure name
Answer:
a) Child structure name. Parent structure name. Member name

Question 15.
A structure variable can be passed to a function in a similar way of passing any argument that is of ……………………. data type.
a) Derived
b) User-defined
c) Built-in
d) None of these
Answer:
c) Built-in

Question 16.
If the structure itself is an argument to a function, then it is called ………………..
a) Call by value
b) Call by Reference
c) Call by Expression
d) None of these
Answer:
a) Call by value

Question 17.
If the reference of the structure is passed as an argument then it is called ……………….
a) Call by value
b) Call by Reference
c) Call by Expression
d) None of these
Answer:
b) Call by Reference

Question 18.
When a structure is passed as an argument to a function using ……………… method, any change made to the contents of the structure variable inside the function to which it is passed do not affect the structure variable used as an argument.
a) Call by value
b) Call by Reference
c) Call by Expression
d) None of these
Answer:
a) Call by value

Question 19.
In ……………….method of passing the structures to functions, any change made to the contents of structure variable inside the function are reflected back to the calling function.
a) Call by value
b) Call by Reference
c) Call by Expression
d) None of these
Answer:
b) Call by Reference

Question 20.
Structures are usually passed by reference method because ……………..
a) It saves the memory space
b) Executes faster
c) Both A and B
d) None of these
Answer:
c) Both A and B

Question 21.
Identify the correct statement from the following.
a) A structured object can also be assigned to another structure object only if both the objects are of the same structure type.
b) The structure elements can be initialized either by using separate assignment statements or at the time of declaration by surrounding its values with braces.
c) Array of structure variable can also be created.
d) All the above
Answer:
d) All the above

Very Short Answers (2 Marks)

Question 1.
What is the drawback of an array?
Answer:
In any situation when more than one variable is required to represent objects of uniform data-types, array can be used. If the elements are of different data types, then array cannot support.
If more than one variable is used, they can be stored in memory but not in adjacent locations. It increases the time consumption while searching.

Question 2.
What is the advantage of structure?
Answer:
The structure provides a facility to store different data types as a part of the same logical element in one memory chunk adjacent to each other.

Question 3.
What are global objects?
Answer:
Objects declared along with structure definition are called global objects

Question 4.
Write note on the anonymous structure.
Answer:
A structure without a name/tag is called an anonymous structure.

Example:
struct
{
long rollno;
int age;
float weight;
} student;
The student can be referred to as a reference name to the above structure and the elements can be accessed like a student, roll no, student.age and student.weight

Question 5.
Define Nested structure.
Answer:
The structure declared within another structure is called a nested structure.

Question 6.
Give an example of nested structure.
Answer:
struct Student
{
int age;
float height, weight;
struct dob
{
int date;
char month[4];
int year;
};
}mahesh;

Question 7.
How to access nested member structure?
Answer:
The nested structures act as members of another structure and the members of the child structure can be accessed as
parent structure name. Child structure name. Member name
Example:
mahesh. dob. date

Short Answers 3 Marks

Question 1.
Write the syntax of defining a structure? Give an example.
Answer:
Structure is declared using the keyword ‘struct’. The syntax of creating a structure is given below.
struct structure_name
{
type member-name1;
type member_name2;
} reference_name;
An optional field reference_name can be used to declare objects of the structure type directly.
Example:
struct Student
{
long rollno;
int age;
float weight;
};

Question 2.
How memory is allocated for a structure?
Answer:
Consider the following structure :
struct Student
{
long rollno;
int age;
float weight;
};
In the above declaration of the struct, three variables rollno, age and weight are used. These variables (data element) within the structure are called members (or fields). In order to use the Student structure, a variable of type Student is declared and the memory allocation is shown in the following figure.

Question 3.
How will you refer structure elements?
Answer:
Referencing Structure Elements
Once the two objects of student structure type are declared, their members can be accessed directly.
The syntax for that is using a dot (.) between the object name and the member name. For example, the elements of the structure Student can be accessed as follows:
balu.rollno
frank, rollno
balu.age
frank.age
balu.weight
frank.weight

Explain In Detail 5 Marks

Question 1.
Explain structure assignments in detail.
Answer:
Structure Assignments
Structures can be assigned directly instead of assigning the values of elements individually.
Example:
If Mahesh and Praveen are same age and same height and weight then the values of Mahesh can be copied to Praveen struct Student
{
int age;
float height, weight;
}mahesh;
The age of Mahesh is 17 and the height and weights are 164.5 and 52.5 respectively.The following statement will perform the assignment.
mahesh = {17, 164.5, 52.5};
praveen = mahesh;
will assign the same age, height and weight to Praveen.