Category: Class 9

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 2 Motion Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 2 Motion

9th Science Guide Motion Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
The area under velocity – time graph represents the
(a) velocity of the moving object.
(b) displacement covered by the moving object,
(c) speed of the moving object.
(d) acceleration of the moving object.
Answer:
(b) displacement covered by the moving object

Question 2.
Which one of the following is most likely not a case of uniform circular motion?
(a) Motion of the Earth around the Sim.
(b) Motion of a toy train on a circular track.
(c) Motion of a racing car on a circular track.
(d) Motion of hours’ hand on the dial of the clock.
Answer:
(c) Motion of a racing car on a circular track

Question 3.
Which of the following graph represents uniform motion of a moving particle?


Answer:

Question 4.
The centrifugal force is
(a) a real force.
(b) the force of reaction of centripetal force.
(c) a virtual force.
(d) directed towards the centre of the circular path.
Answer:
(c) a virtual force

II. Fill in the blanks :

1. Speed is a …………………….quantity whereas velocity is a …………….quantity.
Answer:
Scalar, Vector

2. The slope of the distance – time graph at any point gives ………………
Answer:
Speed

3. Negative acceleration is called ……………………
Answer:
retardation (or) deceleration

4. Area under velocity – time graph shows ……………………………….
Answer:
displacement

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

1. The motion of a city bus in a heavy traffic road is an example for uniform motion.
Answer:
False.
Correct statement: The motion of a city bus in a heavy traffic road is an example for non-uniform motion.

2. Acceleration can get negative value also.
Answer:
True.

3. Distance covered by a particle never becomes zero but displacement becomes zero.
Answer:
True.

4. The velocity – time graph of a particle falling freely under gravity would be a straight line parallel to the x axis. .
Answer:
False.
Correct statement: The velocity – time graph of aparticle moving at uniform do dry. would be straight line parallel to the x axis.

5. If the velocity – time graph of a particle is a straight line inclined to X-axis then its displacement – time graph will be a straight line.
Answer:
True.

IV. Assertion and Reason Type Questions :

Mark the correct choice as:
(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 reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Question 1.
Assertion : The accelerated motion of an object may be due to change in magnitude of velocity or direction or both of them..
Reason : Acceleration can be produced only by change in magnitude of the velocity. It does not depend the direction.
Answer:
(c) If assertion is true but reason is false.

Question 2.
Assertion : The Speedometer of a car or a motor-cycle measures its average speed.
Reason : Average velocity is equal to total displacement divided by total time taken.
Answer:
(d) Assertion is false but reason is true

Question 3.
Assertion : Displacement of a body may be zero when distance travelled by it is not zero.
Reason : The displacement is the shortest distance between initial and final position.
Answer:
(a) Both assertion and reason are true and reason is the correct explanation of assertion

V. Match the Following :

Answer:

VI. Answer briefly :

Question 1.
Define velocity.
Answer:
Velocity is the rate of change of displacement. It. is the displacement in unit time.

Question 2.
Distinguish distance and displacement.
Answer:
Table
Distance

1. The actual length of the path travelled by a moving body irrespective of the direction
2. It is a Scalar quantity

Displacement:

1. The change in position of a moving body in a particular direction
2. It is a Vector quantity

Question 3.
What do you mean by uniform-motion?
Answer:
An object is said to be in uniform motion if it covers equal distances in equal intervals of time how so ever big or small these time intervals may be.

Question 4.
Compare speed and velocity.
Answer:

Speed	Velocity
1. It is the rate of change of distance with respect to time	It is the rate of change of displacement with respect to time
2. It is a scalar quantity having magnitude only	It is a vector quantity having both magnitude and direction
3. Speed is velocity without a particular direction	Velocity is speed in a particular direction
4. It is measured in ms-1 in SI system	It is also measured in ms-1 in a particular direction in SI system
5. Speed in any direction would be a positive quantify, since the distance in any direction is a positive quantity.	Velocity can get both positive and negative values. If velocity in one direction is assumed to be positive then the velocity in the opposite direction would be a negative quantity. Velocity can get zero value also.

Question 5.
What do you understand about negative acceleration?
Answer:
If v < u, i.e. if final velocity is less than initial velocity, the velocity decreases with time and the value of acceleration is negative. It is called negative acceleration. It is also called as retardation (or) deceleration.

Question 6.
Is the uniform circular motion accelerated? Give reasons for your answer.
Answer: When an object is moving with a constant speed along a circular path, the change in velocity is only due to the change in direction. Hence it is accelerated motion.

Question 7.
What is meant by uniform circular motion? Give two examples of uniform circular motion.
Answer:
When an object moves with constant speed along a circular path, the motion is called uniform circular motion.
Example :

• The earth moves around the sun in the uniform circular motion.
• The moon moves in uniform circular motion around the earth.

VII. Answer in detail :

Question 1.
Derive the equations of motion by graphical method.
Answer:
Equations of motion from velocity-time graph:

Graph shows the change in velocity with time of a uniformly accelerated object. The object starts from the point D in the graph with velocity u. Its velocity keeps increasing and after time t it reaches the point B on the graph.
The initial velocity of the object = u = OD = EA
The final velocity of the object = v = OC = EB
Time = t = OE = DA
Also from the graph we know that, AB = DC

1. First equation of motion :

By definition, acceleration = change in velocity / time
= (final velocity – initial velocity)/time
= (OC – OD) / OE
= DC / OE
a = DC /t
DC = AB = at
From the graph EB = EA + AB
v = u + at…………..(1)
This is first equation of motion. .

2. Second equation on of motion :
From the graph the distance covered by the object during time t is given by the area of quadrangle DOEB

s = area of the quadrangle DOEB
= area of the rectangle DOEA + area of the triangle DAB
= (AE x OE) + (1/2 × AB × DA) .
s = ut + 1/2 (at²) …………(2)
This is the second equation of motion.

3. Third equation of motion :
From the graph the distance covered by the object during time, t is given by the area of the quadrangle DOEB. Here DOEB is a trapezium. Then,
s = area of trapezium DOEB
= 1/2 × sum of length of parallel side × distance between parallel sides
= 1/2 × (OD + BE) × OE
S = 1/2 ×× (u + v) × t
since a = (v – u) /1 or t = (v – u) / a
Therefore s = 1/2 × (v + u) x (v – u) / a
2as = v² – u²
v² = u² + 2 as …………….. (3)
This is the third equation of motion.

Question 2.
Explain different types of motion.
Answer:
In physics, motion can be classified as below.

1. Linear motion: Motion along a straight line.

2. Circular motion: Motion along a circular path.

3. Oscillatory motion: Repetitive to and fro motion of an object at regular intervals of time. Random motion: Motion of the object which does not fall in any of the above categories.

Uniform and Non-uniform motion:

Uniform motion: Consider a car that covers 60 km in the first hour, 60 km in the second horn-, and another 60 km in the third hour, and so on. The car covers equal distance at equal intervals of time. We can say that the motion of the car is uniform. An object is said to be in uniform motion if it covers equal distances in equal intervals of time howsoever big or small these time intervals may be.

Non-uniform motion: Now, consider a bus starting from one stop. It proceeds slowly when it passes through a crowded area of the road. Suppose, it manages to travel merely 100 m in 5 minutes due to heavy traffic and is able to travel about 2 km in 5 minutes when the road is clear. Hence, the motion of the bus is non-uniform i.e. it travels unequal distances in equal intervals of time.

VIII. Exercise Problems:

Question 1.
A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10ms^-2, with what velocity will it strike the ground? After what time will it strike the ground?
Answer:
Here we have
Initial velocity, u = 0
Distance, s = 20 m
Acceleration, a = 10 m/s²
Final velocity, v = ?
Time, t = ?

a) Calculation of final velocity, v
We know that, v² = u² + 2as
v² = 0 + 2 × 10m/s² × 20m
v² = 400m²/s²
\(=\sqrt{400 m^{2} / s^{2}}\)
v = 20m/s

b) Calculation of time, t
We know that, v = u + at
20 m/s = 0 + 10m/s² × t
t = \(\frac{20 m / s^{2}}{20 m / s}=2 s\)
∴ Ball will strike the ground at a velocity of 20 ms^-1
Time taken to reach the ground = 2s.

Question 2.
An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 m and 20 s?
Answer:
Here we have
Diameter = 200. m
∴ Radius = 200 m/2 = 100 m
Time of one rotation = 40 s
Time after 2m 20 s = 2 × 60 s +20 s = 140 s
Distance after 140 s = ?
Displacement after 140 s = ?
Circular track with a diameter of 200m
We know that, velocity

a) Distance after 140 s
We know that, distance = velocity × time
= Distance 15.7 rn/s × 140 s
= 2198m

b) Displacement after 2 min 20 s i.e, in 140 s
We know that, distance = velocity × time
Since, rotation in 40 s = 1
∴ Rotation in 1 s = \(\frac{1}{40}\)
∴ Rotation in 140 s = \(\frac{1}{40} \times 140=3.5\)
∴ In 3.5 rotation athlete will be just at the opposite side of the circular track,
i.e. at a distance equal to the diameter of the circular track which is equal to 200m
∴ Distance covered in 2min 20 s = 2198 m
Displacement after 2min 20 5 = 200 m.

Question 3.
A racing car has a uniform acceleration of 4ms-2. What distance it covers in 10s after the start?
Answer:
Here we have
Acceleration, a = 4 m/s².
Initial velocity u = 0
Time t = 10 s
Distance (s) covered =?
We know that, s = ut + \(\frac { 1 }{ 2 }\) at²
s = (0 × 10s) + [\(\frac { 1 }{ 2 }\) × 4 m/s² × (10 s)²]
= \(\frac { 1 }{ 2 }\) × 4 m/s² × 100 s²
= 2 × 100 m = 200 m

Thus, racing car will cover a distance of 200 m after start in 10s with given acceleration.

Intex Activities

ACTIVITY – 1

Look around you. You can see many things: a row of houses, large trees, small plants, flying birds, running cars and many more. List the objects which remain fixed at their position and the objects which keep on changing their position.
Solution:

1. Row of houses, large trees, small plants are the examples, of immovable objects.
2. Flying birds, running cars and buses are the examples of movable objects.

Activity to be done by the students themselves

ACTIVITY – 2

Tabulate the distance covered by a bus in a heavy traffic road in equal intervals of time and do the same for a train which is not in an accelerated motion. From your table what do you understand?
The bus covers unequal distance in equal intervals of time but the train covers equal distances in equal intervals of time.
Solution:

ACTIVITY – 3

Observe the motion of a car as shown in the figure and answer the following questions:
Compare the distance covered by the car through the path ABC and AC. What do you observe? Which path gives the shortest distance to reach D from A? Is it the path ABCD or the path ACD or the path AD?

Solution:

1. Distance covered by the car through the path ABC = 4m + 3m = 7 m. and AC = 5 m. The distance covered by the car through the path ABC is large compared to AC.
2. The shortest distance to resell D from A is path AD = 3m.
3. The total distance covered by the car ABCD A = 14 m. It finally reaches to A.

ACTIVITY – 4

Take a large stone and a small eraser. Stand on the top fit a table and drop them simultaneously from the same height? What do you observe? Now, take a small eraser and a sheet of paper. Drop them simultaneously from the same height. What do you observe? This time, take two sheets of paper having same mass and crumple one of the sheets into a ball. Now, drop the sheet and the ball from the same height. What do you observe?
Solution :
Both the stone and the eraser have reached the surface of the earth almost at the same time.
The eraser reaches first and the sheet of paper reaches later.
The paper crumpled into a ball reaches ground first and plain sheet of paper reaches later, although they have equal mass. It is because of air resistance. The magnitude of air resistance despends on the area of object exposed to air. So the sheet of paper reaches later.

9th Science Guide Motion Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
A particle is moving in a circular pattern of radius r. The displacement after half a circle would be
(a) zero
(b) πr
(c) 2r
(d) 2πr
Answer:
(c) 2r

Question 2.
In which of the following cases of motions, the distance moved and the magnitude of displacement are equal?
(a) If the car is moving in the straight road.
(b) If the car is moving in a circular road.
(c) The earth is revolving around the sun.
(d) The pendulum is moving to and fro
Answer:
(a) If the car is moving in the straight road

Question 3.
A body is thrown vertically upward with velocity, the greatest height h to which it will rise is
(a) u²/2g
(b) u²/g
(c) u/g
(d) u/2g
Answer:
(a) u²/2g

Question 4.
If the displacement of an object is proportional to square of time, then the object moves with
(a) uniform velocity
(b) uniform acceleration
(c) increasing acceleration
(d) decreasing acceleration
Answer:
(b) uniform acceleration

Question 5.
From the given v-t graph, u can be inferred that the object is
(a) in uniform motion
(b) at rest
(c) in non-uniform motion
(d) moving with uniform acceleration
Answer:
(a) in uniform motion

Question 6.
The area under v-t graph represents a physical quantity which has the unit.
(a) m²
(b) m
(c) m³
(d) ms^-1
Answer:
(b) m

Question 7.
m/s² is the unit of
(a) distance
(b) displacement
(c) velocity
(d) acceleration
Answer:
(d) acceleration

Question 8.
The rate of change of displacement
(a) speed
(b) velocity
(c) acceleration
(d) retardation
Answer:
(b) velocity

Question 9.
A scalar quantity has T
(a) magnitude only
(b) direction only
(c) both
(d) none
Answer:
(a) magnitude only

Question 10.
When an object undergoes acceleration
(a) there is always an increase in its velocity
(b) there is always an increase in its speed
(c) a force always acting on it.
(d) all of the above
Answer:
(c) a force always acting on it

Question 11.
A body is projected up with an initial velocity u m/s. It goes up to a height, ‘h’ metres in seconds time. Then it comes back at the point of projection. Considering negligible air resistance, which of the following statement is true?
(a) the acceleration is zero
(b) the displacement is zero
(c) the average velocity is 2hit
(d) the final velocity is 2u when body reaches projection point
Answer:
(b) the displacement is zero

Question 12.
A car accelerates at 1.5m/s²in a straight road. How much is the increase in velocity in 4s.
(a) 6 m/s
(b) 4 m/s
(c) 3 m/s
(d) 2.66 m/s
Answer:
(a) 6 m/s

Question 13.
The slope of the distance-time curve is steeper / greater is the
(a) velocity
(b) acceleration
(c) displacement
(d) speed
Answer:
(d) speed

Question 14.
The given graph represents motion with …………….speed.

(a) uniform
(b) non-uniform
(c) constant
(d) none
Answer:
(b) non-uniform

Question 15.
The relation between displacemeñt and time is given by the equation of
(a) v² = ut + at
(b) s = ut + \(\frac { 1 }{ 2 }\) at²
(e) c = s/t
(d) v² = u² + 2as
Answer:
(b) s = ut + \(\frac { 1 }{ 2 }\) at²

Question 16.
A body moves in a uniform circular motion
(a) It is moving with constant velocity
(b) its acceleration is zero
(c) the body has an acceleration y
(d) none of the above
Answer:
(a) It is moving with constant velocity

Question 17.
Speed of the body in particular direction can be called
(a) acceleration
(b) displacement
(c) velocity
(d) distance
Answer:
(c) velocity

Question 18.
Statement A: Uniform circular motion is a case of accelerated motion
Statement B: In third equation of motion we do not have the term time
(a) Statement B is true, A is false
(b) Statement A is true, B is false
(c) neither statement A nor B is true
(d) both are true
Answer:
(d) both are true

Question 19.
Which of the following is correct about uniform circular motion
(i) direction of motion is continuously changed
(ii) direction of motion is not changed
(iii) speed and direction both remain constant
(iv) speed is constant but direction is changing
(a) ii & iii are correct
(b) i, ii & iii are correct
(c) i & iv are correct
(d) all of these
Answer:
(c) i & iv are correct

Question 20.
Which of the quantities have the same SI unit?
(a) speed, velocity
(b) acceleration, time
(c) velocity, time
(d) velocity, acceleration
Answer:
(a) speed, velocity

Question 21.
Rest and motion of body are
(a) non-relative
(b) not related
(c) relative
(d) none
Answer:
(c) relative

Question 22.
An ant moves from one corner of a room diagonally to the opposite corner. If the dimensions of the hall are 8m x 6m, the displacement of the ant is
(a) 10m
(b) 14m
(c) 28m
(d) 2m
Answer:
(a) 10m

Question 23.
The displacement covered by a second hand of radius V in a clock after one revolution is
(a) 360°
(b) 0
(c) 3r
(d) 2r
Answer:
(b) 0

Question 24.
A man leaves his house at 6.30 a.m. for a morning walk and returns back at 7.30 a.m. after covering 4 km. Displacement covered by him is …………….
(a) 2 km
(b) zero
(c) 8 km
(d) 4 km
Answer:
(b) zero

Question 25.
A body is said to be in non uniform motion if it travels
(a) equal distance in unequal interval of time
(b) equal distance in equal interval of time
(c) unequal distance in unequal interval of time
(d) unequal distance in equal interval of time.
Answer:
(d) unequal distance in equal interval of time

Question 26.
A quantity which has both magnitude and direction is
(a) scalar
(b) distant
(c) vector
(d) moving body
Answer:
(c) vector

Question 27.
A bus accelerating with 4ms-2 changes its speed from 60ms_1 to a certain value in 5s. The final speed is
(a) 40 m/s
(b) 25 ms^-1
(c) 60 ms^-1
(d) 30 ms^-1
Answer:
(a) 40 m/s

Question 28.
A quantity has a value of 16ms-2. It is the
(a) acceleration of an object
(b) velocity of an object
(c) retardation of an object
(d) speed of an object
Answer:
(c) retardation of an object

Question 29.
A boy throws a ball up and catches it when the ball falls back. In which part of the motion the ball is accelerating?
(a) during downward motion
(b) when the ball comes to rest
(c) during upward motion
(d) when the boy catches the ball.
Answer:
(a) during downward motion]

Question 30.
Choose the correct option.
(a) distance is a scalar, velocity is a vector, acceleration is a vector
(b) distance is a vector, velocity is a scalar, acceleration is a vector
(c) distance is a vector, velocity is a vector, acceleration is a vector
(d) distance is a scalar, velocity is a vector, acceleration is scalar
Answer:
(a) distance is a scalar, velocity is a vector, acceleration is a vector

Question 31.
If a moving body comes to rest, then its acceleration is
(a) positive
(b) negative
(c) zero
(d) all of these depending upon initial velocity.
Answer:
(b) negative

Question 32.
If the velocity of a body changes uniformly from u to v in time t, the sum of average velocity and acceleration is


Answer:

Question 33.
Acceleration is defined as the rate of change of
(a) distance
(b) velocity
(c) speed
(d) displacement
Answer:
(b) velocity

Question 34.
When an object undergoes acceleration
(a) there is always an increase in its velocity ‘
(b) there is always an increase in its speed
(c) a force always acting on it.
(d) all the above
Answer:
(c) a force always acting on it

Question 35.
The equation v = u + at gives information as
(a) velocity is a function of time
(b) velocity is a function of position
(c) position is a function of time
(d) position is a function of time and velocity
Answer:
(a) velocity is a function of time

Question 36.
Which of the following can determine the acceleration of a moving object.
(a) area of the velocity-time graph
(b) the slope of the velocity-time graph
(c) area of a distance-time graph
(d) the slope of a distance-time graph
Answer:
(b) slope of the velocity-time graph

Question 37.
What is the slope of the body when it moves with uniform velocity?
(a) positive
(b) negative
(c) zero
(d) may be positive or negative
Answer:
(c) zero]

Question 38.
If a body starts from rest, what can be said about the acceleration of the body?
(a) positively accelerated
(b) negative accelerated
(c) uniform accelerated
(d) none of the above
Answer:
(a) positively accelerated

Question 39.
When a body moves uniformly along the circle then
(a) its velocity changes but speed remain the same
(b) its speed changes but velocity remains the same
(c) both speed and velocity changes
(d) both speed and velocity remains same
Answer:
(a) its velocity changes but speed remains the same

Question 40.
Distance travelled by a freely falling body is proportional to
(a) mass of the body
(b) square of the acceleration due to gravity
(c) square of the time of fall
(d) time of fall
Answer:
(c) square of the time of fall

Question 41.
If the displacement-time graph of a particle is parallel to the time axis, then velocity of the particle is.
(a) infinity
(b) unity
(c) equal to acceleration
(d) zero
Answer:
(d) zero

Question 42.
In the velocity-time graph, AB shows that the body has

(a) uniform acceleration
(b) non-uniform retardation
(c) uniform speed
(d) initial velocity OA & is moving with uniform retardation.
Answer:
(d) initial velocity OA & is moving with uniform retardation

Question 43.
The magnitude of the centripetal force is given by (F= ….)


Answer:

Question 44.
A body moving with an initial velocity 5ms^-1 and accelerates at 2ms ^-2. Its velocity after 10s is
(a) 20ms^-1
(b) 25ms^-1
(c) 5ms^-1
(d) 22.55ms^-1
Answer:
(b) 25ms^-1

Question 45.
In a 100m race, the winner takes 10s to reach the finishing point. The average speed of the winner is
(a) 5ms^-1
b) 20ms^-1
c) 40ms^-1
d) 10ms^-1
Answer:
(d) 10ms^-2

Question 46.
The area under the velocity-time graph represents
(a) the velocity of the moving object
(b) displacement covered by the moving object
(c) speed of the moving object.
(d) acceleration of the moving object
Answer:
(b) displacement covered by the moving object

Question 47.
A car is being driven at a speed of 20ms^-1 when brakes are applied to bring it to rest in 5 s. The deceleration produced in this case will be
(a) +4ms^-2
(b) -4ms^-2
(c) -0.25ms^-2
(d) +0.25ms^-2
Answer:
(b) -4ms^-2

Question 48.
Unit of acceleration is
(a) ms^-1
(b) ms^-2
(c) ms
(d) ms²
Answer:
(b) ms^-2

Question 49.
The force responsible for drying clothes in a washing machine is …………….
(a) Centripetal force
(b) Centrifugal force
(c) Gravitational force
(d) Electro static force
Answer:
(b) Centrifugal force

II. Fill in the blanks:

1. If a body does not change its position, then it is said to be at …………………
Answer:
rest

2. The back and forth motion of a swing is an ………………… motion.
Answer:
Oscillatory

3. In uniform motion an object travels equal ………………… in ………………… interval of time.
Answer:
distances, equal

4. The actual path covered by a body is called …………………
Answer:
distance

5. Displacement is the ………………… distance covered by a body.
Answer:
shortest

6. The motion of the bus is ………………… motion.
Answer:
non-uniform

7. Rate of change of displacement is …………………
Answer:
velocity

8. Speed is a ………………… quantity whereas velocity is a …………………
Answer:
scalar, vector

9. If final velocity is less than initial velocity the acceleration is ………………….
Answer:
negative

10. If final velocity is equal to initial velocity the value of acceleration is ………………….
Answer:
zero

11. The slope of the distance-time graph becomes steeper & steeper the speed ………………….
Answer:
increases

12. A straight line parallel to the x-axis in the velocity-time graph, represents the object moves in…………………
Answer:
uniform velocity

13. From v-t graph ………………… can be calculated.
Answer:
displacement

14. ………………… measures the instantaneous speed of the automobile.
Answer:
Speedometer

15. Slope of the velocity-time graph gives…………………
Answer:
acceleration

16. The value of acceleration for a body at rest is…………………
Answer:
zero

17. At the highest point, when a body is thrown vertically upwards, the velocity is ………………….
Answer:
zero

18. A body moves in a circular pattern the ………………… of velocity does not change but changes.
Answer:
magnitude, direction

19. When a body moves in a circular pattern ………………… acceleration is directed radially towards the centre of the circle.
Answer:
centripetal

20. The separation of cream from milk-hn example for the application of ………………….
Answer:
centrifugal

21. Consider an object is rest at position x = 20m. Then its displacement – time graph will be straight-line ………………… to the time axis.
Answer:
Parallel

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

1. Displacement can be zero but distance never.
Answer:
True.

2. Time is a vector quantity.
Answer:
False.
Correct statement: Time is a scalar quantity.

3. Displacement magnitude can be greater than the distance travelled by the object.
Answer:
True.

4. If the velocity of the body decreases with time the acceleration is negative and the motion is called decelerated motion.
Answer:
True.

5. Acceleration is a scalar.
Answer:
False.
Correct statement: Acceleration is a vector.

6. The area of the velocity-time graph gives the displacement of the body.
Answer:
True.

7. Motion & rest are relative terms.
Answer:
True.

8. An object can be moving with uniform speed but variable acceleration.
Answer:
True.

9. Slope of the distance-time graph indicates the speed.
Answer:
True.

10. It is possible to have object moving with uniform velocity but non-uniform acceleration.
Answer:
True.

11. It is possible to have object moving with uniform speed but variable acceleration.
Answer:
False.
Correct statement : It is possible to have object moving with uniform speed but constant acceleration.

12. The force experienced by a boy in the merry-go-round is a centripetal force.
Answer:
False.
Correct statement: The force experienced by a boy in the merry-go-round is a centrifugal force.

13. The initial velocity of a freely falling object is zero as it is released from rest.
Answer:
True.

IV. Assertion and Reason Type Questions :

(a) If both assertion & reason are true and the reason is the correct explanation of the assertion.
(b) If both assertion & reason are true but the reason is not correct explanation of the assertion.
(c) If the assertion is true but the reason is false.
(d) If assertion & reason both are false.
(e) If assertion is false but reason is true.

Question 1.
Assertion : A body can have acceleration even if its velocity is zero at a given instant of time.
Reason: A body is momentarily at rest when it reverses its direction of motion.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 2.
Assertion : If the displacement of the body is zero, the distance covered by it may not be zero.
Reason: Displacement is a vector & distance is a scalar quantity.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 3.
Assertion: An object can have constant speed but the variable velocity
Reason: Speed is a scalar but velocity is a vector.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 4.
Assertion: The speed of a body can be Negative.
Reason : If the body is moving in the opposite direction of positive motion, then its speed is Negative.
Answer:
(d) Assertion & reason both are false

Question 5.
Assertion : The position-time graph of a uniform motion in one dimension of a body can have Negative slope
Reason : When the speed of body decreases with time then, position-time graph of the moving body has Negative slope.
[Answer:
(c) Assertion is true but the reason is false

Question 6.
Assertion: A positive acceleration of a body can be associated with slowing down of the body.
Reason: Acceleration is a vector.
[Answer: (b) Both assertion & reason are true but the reason is not correct explanation of the assertion]

Question 7.
Assertion :A negative acceleration of a body can be associated with speeding up of the body.
Reason: Increase in speed of a moving body is independent of its direction of motion.
Answer:
(b) Both assertion & reason are true but the reason is not the correct explanation of the assertion

Question 8.
Assertion When a body is subjected to a uniform acceleration, it is always moving in a straight line.
Reason: Motion may be straight-line motion or circular motion.
Answer:
(e) Assertion is false but the reason is true

Question 9.
Assertion : Position-time graph of a stationary object is a straight line parallel to time axis. ’
Reason : For a stationary object, position does not change with time.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 10.
Assertion : The slope of distance-time graph of a body moving with high speed is steeper than slope of distance-time graph of a body with low velocity.
Reason: Slope of distance-time graph = speed of the body.
Answer:
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

V. Answer briefly :

Question 1.
What are centripetal acceleration and centripetal force?
Answer:
When a body moves in a circular pattern the acceleration is directed radially towards the centre of the circle.
The force causing this acceleration is also directed towards the centre of the circle and it is called centripetal force.

Question 2.
Find the magnitude of centripetal force.
Answer:
Consider an object of mass m, moving along a circular path of radius r, with a velocity v, its centripetal acceleration is given by a = v² / r
Hence, the magnitude of centripetal force is given by,
F = mass x centripetal acceleration
F = mv² / r

Question 3.
What is centrifugal force? Give examples.
Answer:
Force acting on a body away from the centre of circular path is called centrifugal force. Thus centrifugal force is in a direction opposite to the direction of centripetal force. Its magnitude is same as that of centripetal force.
Example : Spin dryer of a washing machine, ride on a merry-go-round.

Question 4.
When an object is thrown upwards, what is true of velocity and acceleration at the highest point of motion of the object?
Answer:

• Velocity becomes zero
• Acceleration remains same as g.

Question 5.
Name the two quantities, the slope of whose graph gives (i) speed (ii) acceleration.
Answer:
(i) Distance – Time
(ii) Speed – Time

Question 6.
Define Average speed.
Answer:
It is the total distance travelled divided by the total time taken to cover this distance.

Question 7.
What do you infer if
(i) Distance – time graph is straight line.
(ii) Velocity time graph is curved.
(iii) Displacement time is zig zag.
Answer:
(i) Speed is constant.
(ii) Acceleration is not uniform.
(iii) Non uniform velocity.

Question 8.
Give the formula for each.
(i) Relation between initial, final velocity, acceleration and displacement in a uniformly accelerated straight line motion.
(ii) Relation between initial, final velocity, acceleration & time in a uniformly accelerated straight line motion.
(iii) Relation between initial velocity, acceleration, displacement and time.
Answer:
(i) Relation between initial, final Velocity, acceleration & displacement
in a uniformly accelerated straight line motion. v² = u² + 2as
(ii) Relation between initial, final velocity, acceleration & time
in a uniformly accelerated straight line motion. v = u + at
(iii) Relation between initial velocity, acceleration, displacement and time. s = ut+ 1/2 at²

Question 9.
What is the difference between uniform acceleration and non – uniform acceleration?
Answer:
Uniform Acceleration

1. It is the acceleration in which the object changes its velocity with equal intervals of time.
2. eg. The motion of a ball rolling down.

Non – Uniform Acceleration

1. It is the acceleration in which the object changes its velocity with unequal intervals of time.
2. A car travels 2 km in 1st hour, 3 km in 2nd hour and 3.5 km in 3rd horn.

Question 11.
Define Acceleration.
Answer:
Acceleration is the rate of change of velocity with respect to time or it is the rate of change of velocity in unit time. It is a vector quantity. The SI unit of acceleration is

VI. Paragraph Questions :

Question 1.
Define acceleration and state its SI unit for motion along a straight line, when do we consider the acceleration to be (i) positive (ii) negative? Give an example of a body in uniform acceleration.
Answer:
Answer: Acceleration is the rate of change of velocity with respect to time or it is the rate of change of velocity in unit time. It is a vector quantity. The SI unit of acceleration is ms^-2
Acceleration = Change in velocity/time
= (Final velocity – initial velocity)/time
a = \(\frac{v-u}{t}\)

If v > u, then ‘a’ is positive. If final velocity is greater than initial velocity, the velocity increase with time, the value of acceleration is positive.

If v < u, then a is negative. If final velocity is less than initial velocity
Example : The motion of a freely falling body and vertically thrown up body are the examples of uniform acceleration.
The motion of ball rolling down on an inclined plane is another example.

Question 2.
Distinguish between uniform motion and non
Answer:
uniform motion.

1. An object is said to be in uniform motion if it covers equkl distances in equal intervals of time.
2. example of uniform motion ‘train’

non-uniform motion.

1. If a body covers unequal distances in equal interval of time (or) equal distances in a different interval of time
2. example of non – uniform motion ‘bus’

Question 3.
Define uniform circular motion and give an example of it. Why is it called accelerated motion?
Answer:
When an object is moving with a constant speed along a circular path, the change in velocity is only due to the change in direction. Hence it is accelerated motion. Example:

1. The earth moves around the sun in a uniform circular motion.
2. The moon moves in uniform circular motion around the earth.

Question 4.
When a body is said to be in (i) uniform acceleration (ii) non – uniform acceleration?
Answer:
(i) A body is said to be in uniform acceleration if it travels in a straight line and its velocity increases or decreases by equal amounts in equal time intervals.
(ii) A body is said to be in non-uniform acceleration if the rate of change of its velocity is not constant i.e. differs in different time intervals.

Question 5.
What remains constant in uniform circular motion? And what changes continuously in uniform circular motion?
Answer:

• Speed remains constant in a uniform circular motion.
• Velocity changes continuously in a uniform circular motion.

Problems

Question 1.
A bus speed decreases from 50 km/h to 40 km/h in 3s, find the acceleration of the bus.
Answer:

Question 2.
A car starting from rest moves with uniform acceleration of 0.2 ms-2 for 3 min. Fine the (a) speed acquired (b) the distance travelled.
Answer:
Initial speed (u) = 0 m/s
Acceleration (a) = 0.2 ms^-2
Time taken (t) = 3 min = 3 × 60 = 180 s
Final velocity (v) = ?
Distance covered(s) = ?
v = u + at = 0 + 0.2 × 180 = 36 m/s
v = 36m/s
s = ut + 1/2 at² = 0 + 1/2 × 0.2 × (180)²
= 0.1 × 32400 = 3240 m
s = 3240m

Question 3.
A train is travelling at a speed of 90 kmh^-1. Brakes are applied so as to produce a uniform acceleration of-0.5 ms^-2, find how far the train will go before it is brought to rest.
Answer:
Initial velocity of train (u) = 90 km/h = \(\frac{90,000 \mathrm{~m}}{3,600 \mathrm{sec}}=25 \mathrm{~ms}^{-1}\)
Final velocity (v) = 0 ms^-1
Acceleration (a) = – 0.5 ms^-2
v² = u²+ 2as
s = (v² – u²) / 2a = (0² – 25²) / -(2 × 0.5)
s = -625/-1 = 625m
s = 625m

Question 4.
In a long-distance race the athletes were expected to take four rounds of the track such that the line of finish was same as the line of start. Suppose the length of the track was 300m,

(i) What is the total distance to be covered by the athletes?
What is the total displacement of the athletes when they touch the finish line?
(iii) Is the motion of the athletes uniform or non- D .^starting point uniform?
(iv) Is the displacement & distance moved by an athlete at the end of the race equal?
Answer:
(i) Total distance covered = 4 × 300 = 1200 m
(ii) Displacement = 0 [final position – initial position]
(iii) Non – uniform.
∵ the direction of motion is changing while running on the track.
(iv) Both are not equal.

Question 5.
Ram swims in a 80m long swimming pool. He covers 160m in 1 min by swimming from one end to the other and back along the same straight pattern. Find the average speed and average velocity.
Answer:
Total distance = 160m
Total displacement = 0
Time taken (t) = 1 min = 60s

Question 6.
Abus from Chennai travels to Trichy passes loo km, 160 km at 10.15 am, 11.15 am respectively. Find the average speed of the bus during 10.15 – 11.15 am.
Answer:
The distance coveredbetween 10.l5am& 11.15 am = 160 – 100
= 60km
The time interval = 1 h
Average speed = 60/1
= 60km/h

Question 7.
In a distance-time graph of two objects A & B, which object is moving with greater speed when both are moving?
Answer:
Object B makes a longer angle with the time – axis. Its slope is greater than the slope of object A. Thus the speed of B is greater than that of A.

Question 8.
Find the distance covered by a particle during the time interval which the speed-time graph is-shown in figure.
Answer:

Distance covered in the. time interval 0 to 20s is equal to the area of the triangle OAB.
Area of A OAB. \(\frac { 1 }{ 2 }\) × base × height
\(\frac { 1 }{ 2 }\) × 20 x 20 = 200 ms^-1

Question 9.
A car moves 30 km in 30 min and the next 30 km in 40 min. Calculate the average speed for the entire journey.
Answer:
Answer:
Total time taken = 30 + 40 = 70 min. = \(\frac { 70 }{ 60 }\) hour
Total distance = 30 + 30 = 60 km

Question 10.
A boy travels a distance of 3m due east and then 4m due north.
(a) How much is the total distance covered?
(b) What is the magnitude of the displacement?
Answer:

(a) Total distance covered = 3 + 4 = 7m
(b) Net displacement: OB² = OA² + AB²
= 3² + 4²
OB² = 25m²
∴OB = 5m 0 3m
Net displacement = 5m

Question 11.
During an experiment, a signal from a spaceship reached the ground station in five seconds. What was the distance of the spaceship from the ground station? The signal
travels at the speed of light that is 3 × 10⁸ ms^-1
Answer:
Time taken = 5 seconds.
Speed of signal u = 3 × 10⁸ m/s ?
Distance = ?
Speed = Distance / Time
∴ Distance = Speed × Time
Distance = 3 × 10⁸ × 5 = 15 × 10⁸ m.

Question 12.
A train travelling at a speed of 90kmph. Brakes are applied so as to produce a uniform acceleration of -0.5 ms-2. Find how far the train will go before it is brought to rest?
Answer:
Here we have
Initial velocity , u = 90km/h
\(=\frac{90 \times 1000 \mathrm{~m}}{60 \times 60 \mathrm{~s}}=25 \mathrm{~m} / \mathrm{s}\)
Final velocity, v = 0
Acceleration, a = -0.5m/s²
Thus, distance travelled = ?
We know that, v² = u² + 2as

Question 13.
The adjacent diagram shows the velocity-time graph of the body.
a) During what time interval is the motion of the body accelerated?
Answer:
At 0 to 4 second

b) Find the acceleration in the time Interval mentioned in part ‘a’.
Answer:
\(\mathrm{a}=\frac{v-u}{t}=\frac{30-0}{4}=7.5 \mathrm{~m} / \mathrm{s}^{2}\)

c) What is the distance travelled by the body in the time interval mentioned ¡n part ‘a’?
Answer:Distance travelled Area under the graph
= Area of the triangle = 1/2 bh
= 1/2 × 4 × 30 = 60m

Question 14.
The following graph shows the motion of a car. What do you infer from the graph along with OA and AB? What is the speed of the car along with AB and what time it reached this speed?
a) What do you infer from the graph along OÄ and AB
Answer:
Graph along with OA: The car travels with uniform acceleration and uniform motion.
Graph along with AB : The car travels with constant speed and unaccelerated motion.

b) What is the speed of the car along AB?
Answer:
Along AB : The speed of the car is constant.
From the graph, it seems the speed along AB is 72 km/hr.

c) What time it reached this speed
Answer:
It reaches this speed after 3.2 hours, that is, 3 hours, 12 minutes.

Question 15.
From the following table, check the shape of the graph.

Answer:

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 1 Measurement Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 1 Measurement

9th Science Guide Measurement Text Book Back Questions and Answers

I. Choose the correct answer :

Question 1.
Choose the correct one.
(a) mm < cm < m < km
(b) mm > cm > m > km
(c) km < m < cm < mm
d) mm > m > cm > km
Answer :
(a) mm < cm < m < km

Question 2.
Rulers, measuring tapes and metre scales are used to measure
(a) mass
(b) weight
(c) time
(d) length
Answer:
(d) length

Question 3.
1 metric ton is equal to
(a) 100 quintals
(b) 10 quintals
(c) 1/10 quintals
(d) 1/100 quintals
Answer :
(b) 10 quintals

Question 4.
Which among the following is not a device to measure mass?
(a) Spring balance
(b) Beam balance
(c) Physical balance
(d) Digital balance
Answer :
(a) Spring balance

II. Fill in the blanks :

1. Metre is the unit of …………..
Answer :
length

2. 1 kg of rice is weighed by ……………
Answer :
beam balance

3. Thickness of a cricket ball is measured by ……………..
Answer :
vernier caliper

4. Radius of a thin wire is measured by …………………
Answer :
screw gauge

5. A physical balance measures small differences in mass up to ……………….
Answer :
1mg or less

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

1. The SI unit of electric current is kilogram.
Answer:
False.
Correct statement: The SI unit of electric current is ampere.

2. Kilometre is one of the SI units of measurement.
Answer:
True.

3. In everyday life, we use the term weight instead of mass.
Answer:
True.

4. A physical balance is more sensitive than a beam balance.
Answer:
True.

5. One Celsius degree is an interval of IK and zero degree Celsius is 273.15 K.
Answer:
True.

6 . With the help of vernier caliper we can have an accuracy of 0.1 mm and with screw gauge we can have an accuracy of 0.01 mm.
Answer:
True.

IV. Match the following:

Question 1.

Column I	Column II
Length	kelvin
Mass	metre
Time	kilogram
Temperature	second

Answer:

Column I	Column II
Length	metre
Mass	kilogram
Time	second
Temperature	kelvin

Question 2.

Column I	Column II
Screw gauge	Vegetables
Vernier caliper	Coins
Beam balance	Gold ornaments
Digital balance	Cricket ball

Answer:

Column I	Column II
Screw gauge	Coins
Vernier caliper	Cricket ball
Beam balance	Vegetables
Digital balance	Gold ornaments

V. Assertion and reason type :

Mark the correct answer as :
(a) Both A and R are true but R is not the correct reason.
(b) Both A and R are true and R is the correct reason.
(c) A is true but R is false.
(d) A is false but R is true

Question 1.
Assertion (A) : The scientifically correct expression is “The mass of the bag is 10 kg”
Reason (R) : In everyday life, we use the term weight instead of mass.
Answer :
(a) Both A and R are true but R is not the correct reason

Question 2.
Assertion (A) : 0° C = 273.16 K. For our convenience we take it as 273K after rounding off the decimal.
Reason (R) : To convert a temperature on the Celsius scale we have to add 273 to the given temperature.
Answer :
(b) Both A and R are true and R is the correct reason

Question 3.
Assertion (A) : Distance between two celestial bodies is measured in terms of light year.
Reason (R) : The distance travelled by the light in one year is one light year.
Answer:
(d) A is false but R is true
Distance between two celestial bodies is measured in terms of unit.

VI. Answer very briefly.

Question 1.
Define measurement.
Answer :
Measurement is the process of comparison of the given physical quantity with the known standard quantity of the same nature.

Question 2.
Define a standard unit.
Answer:
Unit is the quantity of a constant magnitude which is used to measure the magnitudes of other quantities of the same nature.

Question 3.
What is the full form of SI system?
Answer:
The full form of S.I. system is the International System of Units.

Question 4.
Define least count of any device.
Answer:
Least count is the least measurement possible in a given device.
It is the distance moved by the tip of the screw for a rotation of one division on the head scale.
Least count = [Pitch / No. of head scale divisions]

Question 5.
What do you know about pitch of screw gauge?
Answer:
Pitch of the screw gauge is the distance between two successive screw threads. It is measured by the ratio of distance travelled on the pitch scale to the number of rotations of the head scale.

Question 6.
Can you find the diameter of a thin wire of length 2 m using the ruler from your instrument box?
Answer:
No, I can not find the diameter of a thin wire of length 2 m using the ruler.

VII. Answer briefly :

Question 1.
Write the rules that are followed in writing the symbols of units in SI system.
Answer:

•  The units named after scientists are not written with a capital initial letter.
  E.g. newton, henry, ampere, and watt.
• The symbols of the units named after scientists should be written by the initial capital letter.
  E.g. N for newton, H for Henry, A for ampere, and W for watt.
• Small letters are used as symbols for units not derived from a proper noun.
  E.g. m for metre, kg for kilogram.
•  No lull stop or other punctuation marks should be used within or at the end of symbols.
  E.g. 50 m and not as 50 m.
•  The symbols of the units are not expressed in plural form.
  E.g. 10 kg not as kgs.

Question 2.
Write the need of a standard unit.
Answer:
A Standard Unit is needed to maintain uniformity in measurements like length, weight, size and distance. Eg: Standard Unit of length is metre.

Question 3.
Differentiate mass and weight.
Answer:
Mass:

1.  Fundamental quantity
2.  Has magnitude alone – scalar quantity
3.  It is the amount of matter contained in a body
4.  Remains the same
5.  It is measured using physical balance
6.  Its unit is kilogram

Weight:

1.  Derived quantity
2.  Has magnitude and direction – vector quantity
3.  It is the normal force exerted by the surface on the object against gravitational pull
4.  Varies from place to place
5.  It is measured using spring balance
6.  Its unit is newton

Question 4.
How will you measure the least count of vernier caliper?
Answer:
The least count of Vernier Caliper is the ratio of the value of one smallest main scale division to total
a number of Vernier scale divisions.
i.e., L.C. = 0.1mm = 0.01cm
(or) L.C. = 1MD – 1VSD = 1.0 mm – 0.9 mm = 0. 1mm = 0.01 cm

VIII. Answer in detail :

Question 1.
Explain a method to find the thickness of a hollow teacup.
Answer:
Step 1 : The Pitch, Least count and the type of zero error of the screw gauge are determined.
Step 2 : The given cup is placed in between two studs.
Step 3 : The head screw using the ratchet arrangement is freely rotated until the given cup is held firmly, but not tightly.
Step 4 : Pitch scale reading (PSR) by the head scale and head scale coincidence (HSC) with the axis of the pitch scale, are found.
Step 5 : The readings are recorded and the experiment for different positions of the given cup is repeated.
Step 6 : The thickness of the cup is calculated using the formula P.S.R + (HSC × L.C)
Step 7 : Then the average of the last column of the table, is found. Hence the thickness of a hollow tea cup = ………….. mm.

Question 2.
How will you find the thickness of a one rupee coin?
Answer:
Step 1 : The Pitch, Least count and the type of zero error of the screw gauge are determined.
Step 2 : The given coin is placed in between two studs.
Step 3 : The head screw using the ratchat arrangement is freely rotated until given one rupee coin is held firmly, but not tightly.
Step 4 : Pitch scale reading (PSR) by the head scale and head scale coincidence (HSC) with are axis of the pitch scale are found.
Step 5 : The reading are recorded and the experiment for different positions of the given coin is repeated.
Step 6 : The thickness of the coin is computed using the formula P.S.R + (HSC x L.C )
Step 7 : Then the average of the last column of the table is found.

mean = …………….. mm
Hence the thickness of a one rupee coin = ……………….. mm

IX. Numerical Problems :

Question 1.
Inian and Ezhilan argue about the light year. Inian tells that it is 9.46 x 10¹⁵m and Ezhilan argues that it is 9.46 x 1012 km. Who is right? Justify your answer.
Answer:
(Inian is correct)
Light travels 3 × 10⁸m in one second or 3 Lakhs kilometre in one second.
In one year we have 365 days.
The total number of second in one year is equal to 365 x 24 x 60 x 60
Distance travelled by light in 1 year = (3.153 x 10⁷) x (3 x 10⁸)
= 9.46 x 10¹⁵m

Question 2.
The main scale reading while measuring the thickness of a rubber ball using Vernier caliper is 7 cm and the Vernier scale coincidence is 6. Find the radius of the ball.
Answer:
MSR = 7 cm
VC = 6cm
LC = 0.1mm = 0.1cm
Diameter = DR = MSR + (VC X LC)
= 7 + 0.06 cm
Diameter D = 7.06 cm
Radius R = \(\frac{D}{2}=\frac{7.06}{2}\) = 0.035 m
The radius of the ball = 0.0353 m.

Question 3.
Find the thickness of a five rupee coin with the screw gauge, if the pitch scale reading is 1 mm and its head scale coincidence is 68.
Answer:
PSR = 1 mm = 1 x 10^-3m
HSC = 68
LC = 0.01 mm =0.01 × 10^-3m
Total reading = PSR + (HSC × LC)
∴Thickness of the five rupee coin = 1 × 10^-3 + (68 × 0.01 × 10^-3 )m
∴ Thickness of the five rupee coin = 1.68 × 10^-3m = 1.68mm

Question 4.
Find the mass of an object weighing 98 N.
Answer:
W = mg
W =98 N
g = 9.8 m/s²
m = \(\frac{\mathrm{W}}{\mathrm{g}}=\frac{98}{9.8}\) = 10 kg

Intext Activities

ACTIVITY – 1

Using Vernier caliper find the outer diameter of your pen cap.

Aim : To find the outer diameter of the pen cap.
Materials required : Vernier caliper, pen cap.
Answer:

Result: The outer diameter of the pen cap = 9.35 cm
[End of the activity]

ACTIVITY – 2

Determine the thickness of a single sheet of your science textbook with the help of a Screw gauge.

LC = Least Count
PSR = Pitch Scale Reading
HSC = Head Scale Coincidence
HSR = Head Scale Reading
TR = Total Reading
Result : The thickness of the single sheet = 0.30
End of the activity

9th Science Guide Measurement Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
Length is ……………….
(a) The amount of matter in an object
(b) The amount of space an object takes up.
(c) The distance between two points.
(d) The amount of stuff in an object
Answer:
(c) The distance between two points

Question 2.
Mass is ………………….
(a) The distance between two points
(b) The distance between three points
(c) The amount of matter contained in an object
(d) The amount of space an object occupies.
Answer:
(c)The amount of matter contained in an object

Question 3.
Unit used to measure length
(a) metre
(b) litre
(c) gram
(d) cubic metre (m³)
Answer:
(a) metre

Question 4.
Unit which is used to measure mass
(a) ml
(b) 1
(c) cm
(d) gram
Answer:
(d) gram

Question 5.
How many metres are there in 1 nanometer?
(a) 10^-10m
(b) 10^-9m
(c) 10⁹m
(d) 10¹⁰m
Answer:
(b) 10^-9m

Question 6.
What unit will you use to measure the length of our classroom?
(a) km
(b) m
(c) cm
(d) mm
Answer :
(b) m

Question 7.
The Kelvin is the basic unit of ………………..
(a) temperature
(b) mass
(c) length
(d) volume
Answer :
(a) temperature

Question 8.
……………….consists of ‘U’ shape metal frame
(a) Screw gauge
(b) Vernier caliper
(c) Beam balance
(d) Spring balance
Answer :
(a) screw gauge

Question 9.
Least count of a vernier caliper is ……………. cm.
(a) 1
(b) 0.1
C) 0.01
(d) 0.001
Answer:
(c) 0.01

Question 10.
If no object is placed on the hook, then the pointer of the spring balance reads ………………….
(a) 3
(b) 2
(c) 1
(d) 0
Answer :
(d) 0

Question 11.
SI unit of mass and weights are ………………….
(a) kg, N
(b) N, kg
(c) K, N
(d) N, K
Answer:
(a) kg, N

Question 12.
Units named after scientists …………………..
(a) lowercase
(b) upper case
(c) both (a) and (b)
(d) neither (a) or (b)
Answer:
(a) lower case

Question 13.
An instrument that is used to measure the diameter of a cricket ball is ………………….
(a) Screw gauge
(b) Meter scale
(c) Vernier caliper .
(d) Spring balance
Answer:
(a) Vernier caliper

Question 14.
Distance between Chennai and Kanyakumari can be found in
(a) Kilometres
(b) Metres
(c) Centimetres
(d) Millimetres.
Answer:
(a) Kilometres

II. Fill in the blanks :

1. The precision of vernier calipers is ……………. mm.
Answer:
(a) 0.1mm

2. The gravity accelerates an object, the distance fallen is proportional to …………………
Answer:
time squared

3. SI unit of electric current is ………………
Answer:
ampere

4. Larger unit for measuring time is ………………..
Answer:
millennium

5. The value of an astronomical unit is ……………………
Answer:
1.496 x 10¹¹

6. Mass is a …………….. quantity.
Answer:
scalar

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

1. The precision of screw gauge is 0.001 cm.
Answer:
True.

2. The unit of amount of substance is candela
Answer:
False.
Correct statement: The unit of amount of substance is mole.

3. The symbol for the units derived from the names of scientists are written in capital letter
Answer:
True.

4. Yard was used as the unit of length.
Answer:
True

5. Micron is also known as micro-metre
Answer:
True

6. A vemier caliper using the scale invented by Galileo.
Answer:
False.
Correct statement: A vernier caliper using the scale invented by Pierre Vernier.

7. The SI unit of mass is kg.
Answer:
True.

8. Weight has both magnitude and direction.
Answer:
True.

IV. Match the following:

Question 1.

Column I	Column II
FPS	Metre, kilogram and second
CGS	Foot, pound and second
MKS or SI	centimetre, gram and second

Answer:

Column I	Column II
FPS	Foot, pound and second
CGS	centimetre, gram and second
MKS or SI	Metre, kilogram and second

Question 2.

Column-I	Column-II
10 years	1 year
10 centuries	1century(100 years)
10 decades	1 millennium
365.24 days	1 decade

Answer:

Column-I	Column-II
10 years	1 decade
10 centuries	1 millennium
10 decade	1century(100 years)
365.24 days	1 year

Question 3.

Column-I	Column-II
Electric Current	radian
Luminous intensity	ampere
Angle	steradian
Solid angle	candela

Answer:

Column-I	Column-II
Electric Current	ampere
Luminous intensity	candela
Angle	radian
Solid angle	steradian

Question 4.

Column-I	Column-II
Length	s
Mass	m
Time	k
Temperature	kg

Answer:

Column-I	Column-II
Length	m
Mass	kg
Time	s
Temperature	k

Question 5.

Column-I	Column-II
Millimeter	10-15 m
Nanometer	10-3m
Angstrom	10-9m
Fermi	10-10m

Answer:

Column-I	Column-II
Millimeter	10-3m
Nanometer	10-9m
Angstrom	10-10m
Fermi	10-15 m

Question 6.

Column-I	Column-II
Temperature	Bearm balance
Mass	Ruler
Length	Digital clock
Time	Thermometer

Answer:

Column-I	Column-II
Temperature	Thermometer
Mass	Bearm balance
Length	Ruler
Time	Digital clock

V. Assertion and reason type :

Question 1.
Assertion (A) : Light year and wave length both measure distance
Reason (R) : Both have dimensions of time.
(a) Both A and R are true but R is not the correct explanation of A.
(b) Both A and R are true and R is the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Answer :
(c) A is true but R is false

Question 2.
Assertion (A) : Density is a derived physical quantity
Reason (R) : Density cannot be derived from the fundamental physical quantities.
(a) Both A and R are true but R is not the correct explanation of A.
(b) Both A and R are true and,R-is the correct explanation of A.
(c) A is true but R is false. .
(d) A is false but R is true.
Answer :
(c) A is true but R is false
Correct statement: Density can be derived from mass and volume.

Question 3.
Assertion (A) : Mass, Length and Time are fundamental physical quantities.
Reason (R) : They are independent of each other.
(a) Both A and R are true but R is not the correct explanation of A.
(b) Both A and R are true and R is the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Answer :
b) Both A and R are true and R is the correct explanation of A

Question 4.
Assertion (A) : The SI system of units is the improved system of units for measurement.
Reason (R) : The SI unit of mass is kilogram.
(a) Both A and R are true but R is not the correct reason.
(b) Both A and R are true and R is the correct reason.
(c) A is true but R is false.
(d) A is false but R is true.
Answer :
(b) Both A and R are true and R is the correct reason

Question 5.
Assertion (A) : The skill of estimation is important for all of us in our daily life.
Reason (R) : The skill of estimation reduces our consumption of time.
a) Both A and R are true but R is not the correct reason.
b) Both A and R are true and R is the correct reason.
c) A is true but R is false. ,
d) A is false but R is true.
Answer :
(b) Both A and R are true and R is the correct reason

VI. Comprehensive type :

(a) The speed of a body gives us an idea of how slow or fast that a body is moving. Speed of a body is the distance travelled by it per unit time. The SI unit of speed is metre per second. It is a scalar quantity. The speed of a running cab at any instant of time is shown by an instrument called, ’speedometer’ and the distance travelled by a car is measured by another instrument called, ‘odometer’.

Question 1.
Which the following is not a correct unit of speed?
(a) cm/s
(b) m/s
(e) km/h
(d) km/s.
Answer :
(d) km/s

Question 2.
If the distance travelled by the cab in 3 hours is 120 km, then its speed will be
(a) 40 m/s
(b) 40 km/s
(c) 40 km/h
(d) 40 km/min
Answer :
(c) 40 km/h

Question 3.
The formula for finding the speed of the cab is
(a) Distance = speed x time
(b) velocity = distance x time
(c) time = distance x velocity
(d) None of these.
Answer:
(a) Distance = speed x time

(b) Read the passage and answer the questions given below.

Mass is the amount of matter contained in an object. Measurement of mass helps us to distinguish between lighter and a heavier body. Beam-Balance, spring balance and electronic balance are used to measure mass of different objects. The SI unit of mass is kilogram (kg). But different units are Used to measure the mass of different objects depending upon their weight, e.g. weight (mass) of a tablet is measured in milligrams (mg), weight of a student is measured in kilogram (kg), and weight of a truck with goods is measured in metric tons. 1 metric ton is equal to 10 quintals and 1 quintal is equal to 100 kg. 1 gram is equal to 1000 mg.

Question 1.
The value of 1 metric ton is equal to
(a) 1000 kg
(b) 10 quintals
(c) 1000,000 g
(d) 100 kg
Answer :
(a) 1000 kg (or) (b) 10 quintals

Question 2.
How will you measure weight of a tablet?
(a) kg
(b) g
(c) mg
(d) none of these.
Answer:
(c) mg

VII. Answer very briefly :

Question 1.
Write the units which are used to measure long distances.
Answer:
km, AU, light-year, parsec.

Question 2.
Define Astronomical unit.
Answer:
AU is defined as the average distance between the earth and the sun.
1 AU = 1.496 × 10¹¹m.

Question 3.
Define the light year.
Answer:
The distance travelled by light in one year in vacuum. 1 light-year = 9.46 × 10¹⁵m.

Question 4.
Convert the temperature from Fahrenheit into Celsius & Kelvin.
Answer:

Question 5.
Convert 100°C into Kelvin.
Answer:
100 + 273 = 373 K. ie. °C + 273

Question 6.
Convert 112°F into K.
Answer:

Question 7.
Write the principle of screw gauge.
Answer:

• When a screw is rotated in a nut, the distance moved by the tip of the screw is directly proportional to the number of rotations given.
• Hence the principle of the screw is considered as the principle of screw gauge.

Question 8.
What are the kinds of units?
Answer:

1. Fundamental or basic units
2. Derived units

Question 9.
Give some examples of fundamental units.
Answer:
The examples of fundamental units are kg for mass,m for length, s for time.

Question 10.
Give some examples of derived units.
Answer:
The units of area, volume, density.

Question 11.
What is the standard unit of weight?
Answer:
Newton is the standard unit of weight.

Question 12.
What is the standard unit of mass?
Answer:
kilogram is the standard unit of mass.

Question 13.
Define Mass.
Answer:
Mass is the amount of matter contained in a body.

Question 14.
Define Weight.
Answer:
The force with which the earth attracts a body towards its center is called weight.

Question 15.
What is the SI unit of temperature?
Answer:
Kelvin is the SI unit of temperature.

Question 16.
What is the measuring unit of the thickness of a plastic carry bag?
Answer:
1 micron = 10^-6m (or) μm.

VIII. Answer briefly :

Question 1.
Write temperature conversion.
Answer:
Temperature Conversion (Exact)

Question 2.
Write about the positive zero error in screw gauge instrument.
Answer:
When the plane surface of the screw and the opposite plane stud on the frame are brought into contact, if the zero of the head scale lies below the pitch scale axis, the zero error is positive. For example, the 5th division of the head scale coincides with the pitch scale axis, then the zero error is positive and is given by Z.E = + (n × LC) where ‘n’ is the head scale coincidence. In this case, Zero error = + (5 × 0.01) = 0.05 mm. So the zero correction is – 0.05 mm

Question 3.
Write SI units for the fundamental quantity.
Answer:

Basic Quantity	Unit
Length	metre
Mass	kilogram
Time	second
Electric current	ampere
Temperature	kelvìn
Amount of substance	mole
Luminous intensity	candela

Question 4.
Convert the following units in metre.
Answer:

Smaller units	Value in metre
Centimeter (cm)	10-2 m
Millimeter (mm)	10-3 m
micron or µm	10-6 m
nanometre (nm)	10-9 m
angstrom (A)	10-10 m
fermi (f)	10-15 m

Question 5.
Draw and mark the parts of vernier caliper
Answer:
PARTS Marked in the Vernier caliper

1. Lower fixed jaw
2. Upper fixed jaw
3. Lower movable jaw
4. Vernier scale
5. Retainer
6. Main scale
7. Depth probe.

IX. Numerical Problems :

Question 1.
A piece of iron of volume 40cm³ whose density is 6.8g/cm³. Find the mass of iron.
Answer:
Given, density of iron, D = 6.8g/cm³
volume of iron, V = 40 cm³
mass of iron, M = V × D [∴ mass = volume × density]

m = 272.0g.

Question 2.
Solve : The mass of 40 apples in a box is 5 kg.
(i) Find the mass of a dozen of them.
(ii) Express the mass of one apple in gram.
Answer:
(i)  40 apple = 5 kg 5000 g
1 apple =\(\frac{500 \not 0}{4 \not \emptyset}\)
1 apple 125 g
∴ 1 dozen 12 apples
12 apples 125 × 12 g
12 apples 1500 g.

(ii)  40 apples = 5000 g

1 apple = \(\frac{5000}{40} \mathrm{~g}\)

1 apple = 125 g
The mass of 1 apple = 125 g

X. Answer in detail :

Question 1.
How will you find Zero Error of the screw gauge?
Answer:
Zero Error of a screw gauge :
When the plane surface of the screw and the opposite plane stud on the frame area brought into contact, if the zero of the head scale coincides with the pitch scale axis there is no zero error.

Positive zero error:
When the plane surface of the screw and the opposite plane stud on the frame are brought into contact, if the zero of the head scale lies below the pitch scale axis, the zero error is positive. For example, the 5th division of the head scale coincides with the pitch scale axis, then the zero error is positive and is given by
Z.E = + (n x LC) where ‘n’ is the head scale coincidence. In this case, Zero error = + (5 x 0.01) = 0.05mm. So the zero correction is -0.05 mm.

Negative zero error:
When the plane surface of the screw and the opposite plane stud on the frame are brought into contact, if the zero of the head scale lies above the pitch scale axis, the zero error is negative. For example, the 95th division coincides with the pitch scale axis, then the zero error is negative and is given by
ZE = -(100-n) × LC
ZE = – (100 – 95) × LC
= -(5 × 0.01)
= – 0.05 mm
The zero correction is + 0.05mm

Question 2.
How will you find Zero Error of Vernier Caliper? Explain.
Answer:
Zero error:

• Unscrew the slider and move it to the left, such that both the jaws touch each other. Check whether the zero marking of the main scale coincides with that of the Vernier scale.
• If they are not coinciding with each other, the instrument is said to posses zero error. Zero error may be positive or negative.
• If the zero mark of the Vernier is shifted to the right, it is called positive error.
• On the other hand, if the Vernier zero is shifted to the left of the main scale zero marking, then the error is negative.

Positive zero error:

• From the figure you can see that zero of the vernier scale is shifted to the right of zero of the main scale.
• In this case the reading will be more than the actual reading.
• Hence, this error should be corrected. In order to correct this error, find out which vernier division is coinciding with any of the main scale divisions.
• Here, fifth vernier division is coinciding with a main scale division.
• So, positive zero error = +5 × LC = +5 × 0.01 = 0.05 cm.
  

Negative zero error:

• You can see that zero of the vernier scale is shifted to the left of the zero of the main scale.
• So, the obtained reading will be less than the actual reading.
• To correct this error we should first find which vernier division is coinciding with any of the main scale divisions, as we found in the previous case.
• In this case, you can see that sixth line is coinciding. But, to find the negative error, we can count backward (from 10).
• So, the 4th line is coinciding. Therefore, negative zero error = -4 x LC = -4 x 0.01 = -0.04 cm.
  

Question 3.
Write short note on the following :
(i) Common balance
(ii) Physical balance Digital balance Spring balance
Answer:
Common (beam) balance :
A beam balance compares the sample mass with a standard reference mass (Standard reference masses are 5g, 10g, 20g, 50g, 100g, 200g, 500g, 1kg, 2kg, 5kg). This balance can measure mass accurately up to 5 g

Physical balance:
This balance is used in labs and is similar to the beam balance but it is a lot more sensitive and can measure mass of an object correct to a milligram.
The standard, reference masses used in this physical balance are 10 mg, 20 mg, 50 mg, 100 mg, 200 mg, 500 mg, 1 g, 2g, 5 g, 10 g, 20 g, 50 g, 100g, and 200 g.

Digital balance:
Nowadays, for accurate measurements digital balances are used, which measure mass accurately even up to a few milligrams, the least value being 10 mg (Figure 1.11). This electrical device is easy to handle and commonly used in jewellery shops and labs.

Spring balance:
This balance helps us to find the weight of an object. It consists of a spring fixed at one end and a hook attached to a rod at the other end. It works by ‘Hooke’s law’ which states that the addition of weight produces a proportional increase in the length of the spring. A pointer is attached to the rod which slides over a graduated scale on the right. The spring extends according to the weight attached to the hook and the pointer reads the weight of the object on the scale.

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 4 Electric Charge and Electric Current Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 4 Electric Charge and Electric Current

9th Science Guide Electric Charge and Electric Current Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
In current electricity, a positive charge refers to,
(a) presence of electron
(b) presence of proton
(c) absence of electron
(d) absence of proton
Answer:
(c) absence of electron

Question 2.
Rubbing of comb with hair
(a) creates electric charge
(b) transfers electric charge
(c) either (a) or (b)
(d) neither (a) nor (b)
Answer:
(b) transfers electric charge

Question 3.
Electric field lines ……………….. from positive charge and ……………………..in negative charge.
(a) start; start
(b) start; end
(c) start: end
(d) end; end
Answer:
(b) or (c) start, end

Question 4.
Potential near a charge is the measure of its……………to bring a positive charge at that point.
(a) force
(b) ability
(c) tendency
(d) work
Answer:
(d) work

Question 5.
Heating effect of current is called,
(a) Joule heating
(b) Coulomb heating
(c) Voltage heating
(d) Ampere heating
Answer:
(a) Joule heating

Question 6.
In an electrolyte, the current is due to the flow of
(a) electrons
(b) positive ions
(c) both (a) and (b)
(d) neither (a) nor (b)
Answer:
(c) both (a) and (b)

Question 7.
Electroplating is an example of
(a) heating effects
(b) chemical effects
(c) flowing effects
(d) magnetic effect
Answer:
(b) chemical effect

Question 8.
Resistance of a wire depends on,
(a) temperature
(e) nature of material
(b) geometry
(d) all the above
Answer:
(d) all the above

II. Match the following

1. Electric Charge	(a) ohm
2. Potential difference	(b) ampere
3. Electric field	(c) coulomb
4. Resistance	(d) newton per coulomb
5. Electric current	(e) volt

Answer:
1 – c, 2 – e, 3 – d, 4 – a, 5 – b

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

1. Electrically neutral means it is either zero or equal positive and negative charges.
Answer:
True.

2. Ammeter is connected in parallel in an electric circuit.
Answer:
False.
Correct statement: Ammeter is connected in series in an electric circuit.

3. The anode in the electrolyte is negative.
Answer:
False.
Correct statement: The anode in the electrolyte is positive.

4. Current can produce the magnetic field.
Answer:
True.

IV. Fill in the blanks :

1. Electrons move from …………….. potential to …………….. potential.
Answer:
lower, higher

2. The direction opposite to the movement of electron is called …………….. current.
Answer:
conventional

3. The e.m.f of a cell is analogues to a pipeline.
Answer:
water pump

4. The domestic electricity in India is an ac with a frequency of Hz.
Answer:
50

V. Conceptual Questions:

Question 1.
A bird sitting on a high power electric line is still safe. How?
Answer:
Birds don’t get shocked when they sit on electrical wires because they are not good conductors of electricity. Electricity flowing through a single power line at 35,000 volts will continue along the path of least resistance and bypass birds because there is no difference in electrical potential.

Question 2.
Does a solar cell always maintain the potential across its terminals constant? Discuss.
Answer:
Solar cell delivers a constant current for any given illumination level, while the voltage is determined by the load resistance. Potential in a solar cell depends on the intensity of solar radiation. Since the intensity of solar radiation is not always constant, the potential across its terminal is also not constant.

Question 3.
Can electroplating be possible with the alternating current?
Answer:
Electroplating is a process where there is a continuous flow of ions for the deposition of copper, which is not possible in an Alternating current. Therefore, electroplating is possible with DC only, for the sake of perfectness and homogeneity of the electroplating.

VI. Answer the following:

Question 1.
On what factors does the electrostatic force between two charges depend?
Answer:
The electrostatic force between two charges depend on the following factors;

• value of charges on them,
  
• distance between them, and
  
• nature of medium between them.

Question 2.
What are the electric lines of force?
Answer:
The lines representing the electric field are called electric lines of force.

Question 3.
Define electric field.
Answer:
The electric lines of force are straight or curved paths along which a unit positive charge tends to move in the electric field.

Question 4.
Define electric current and give its unit.
Answer:
The electric current is defined as the rate of flow of electric charge through any section of a conductor.
Electric current I = Q/t
Its unit is Cs^-1
Its SI unit: ampere (A).

Question 5.
State Ohm’s law.
Answer:
Ohm’s law states that electric potential difference across two points in an electrical circuit is directly proportional to the current passing through it. That is V ~ I
The proportionality constant is the resistance (R) offered between the two points.
Hence, Ohm’s law is written as V = RI (or) V = IR
Where, V is the potential difference in volt (V), I is the current flow in ampere (A), R is the resistance in ohm (Ω)

Question 6.
Name any two appliances which work under the principle of heating effect of current.
Answer:
Electric heating appliances like an iron box, water heater, toaster, etc.

Question 7.
How are the home appliances connected in general, in series or parallel? Give reasons.
Answer:
The home appliances are connected in parallel. This is because, when the appliances are connected in parallel, each of them can be switched on and off independently. This is a feature that is essential in house wiring. Also, if the appliances were wired in series, the potential difference across each appliance would vary depending on the resistance of the appliance.

Question 8.
List the safety features whilehandling electricity.
Answer:
(i) Ground connection: The metal bodies of all the electrical appliances are to be connected to the ground by means of a third wire apart from the two wires used for electrical connection.

(ii) Trip switch: It is an electromechanical device which does not allow a current beyond a particular value by automatically switching off the connection.

(iii) Fuse: A fuse is another safety mechanism which works on the joule heating principle.

VII. Exercises:

Question 1.
Rubbing a comb on hair makes the comb get – 0.4C.
(a) Find which material has lost electron and which one gained it.
(b) Find how many electrons are transferred in this process.
Answer:
a. Comb gained electrons. Dry hair lost an electron
b. No. of electrons transferred = -0.4 C
1 coulomb = 6.25 × 10¹⁸ electron
– 0.4 C = 0.4 × 6.25 × 10¹⁸ electrons
= -2.5 × 10¹⁸ electrons

Question 2.
Calculate the amount of charge that would flow in 2 hours through an element of an electric bulb drawing a current of 2.5A.
Answer:
Current I = 2.5 A
time t = 2 hours = 2 × 3600 seconds
t = 7200 s
Amount of charge Q = I × t = 2.5 × 7200
Q = 18,000

Question 3.
The values of the current (I) flowing through a resistor for various potential differences V across the resistor are given below. What is the value of resistor?

[Hint: plot V-I graph and take slope]
Answer:

Intext Activities

ACTIVITY – 1

Take a condemned electronic circuit board in a TV remote or old mobile phone. Look at the electrical symbols used in the circuit. Find out the meaning of the symbols known to you.


[End of the activity]

ACTIVITY – 2
Cut an arrow shaped strip from aluminium foil. Ensure that the head is a fine point. Keep the arrow shaped foil on a wooden board. Connect a thin pin to two lengths of wire. Connect the wires to the terminals of electric cell, may be of 9V. Press one pin onto the pointed tip and the other pin at a point about one or two mm away. Can you see that the tip of aluminum foil starts melting?

Aim :
To understand the heating effect of electric current.

Materials Required :
Aluminum strip, wooden board, bell pins, cell of 9 V.

Procedure :
Cut an arrow shaped strip from aluminum foil. Keep the arrow shaped foil on a wooden board. Connect a pin to two lengths of wire. Connect the wires to the terminals of electric cell of 9 V. Press one pin onto the pointed tip and another pin at a point about one or two mm away.

Observation :
The tip’of aluminum foil starts melting.

Conclusion :
It starts melting because the electrons while moving in the wire suffer resistance. Work is done to overcome the resistance which is converted into heat energy. This conversion of electrical energy into heating energy is called the heating effect of electric current.

ACTIVITY – 3

Take a beaker half filled with copper sulphate solution. Take a carbon rod from a used dry cell. Wind a wire on its upper end. Take a thick copper wire, clean it well and flatten it with a hammer. Immerse both the copper wire and carbon rod in the copper sulphate solution. Connect the carbon rod to the negative terminal of an electric cell and copper wire to the positive terminal of the cell. Also ensure that the copper and the carbon rod do not touch each other, but are close enough. Wait and watch. After some time you would find fine copper deposited over the carbon rod. This is called as electroplating. This is due to the chemical effect of the current.

Aim:
Electroplating carbon rod with copper.

Materials Required:
Beaker, copper sulphate solution, carbon rod, thick copper wire and hammer.

Procedure :

• Take a beaker half filled with copper sulphate solution.
• Take a carbon rod and wind a wire on its upper end.
• Take a thick copper wire, clean it well and flatten it with a hammer.
• Immerse both the copper wire and carbon rod in the copper sulphate solution.
• Connect the carbon rod to the negative terminal of the cell and copper wire to the positive terminal of the cell.
• Ensure both the rods do not touch each other, but are close enough.
• Observe for some time.

Observation :
After some time, we would find fine copper deposited over the carbon rod.

Conclusion :
When the current passes through the copper sulphate solution, the copper ions migrate from the copper sulphate solution towards the cathode (-ve terminal). These copper ions get deposited on the carbon rod and form a coating of a fine layer on it.

This process of coating a metal over another metal by electrolysis is called electroplating. This is due to the chemical effect of electric current.

9th Science Guide Electric Charge and Electric Current Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
A current of 2A passing through the conductor produces 80 J of heat in 10 seconds. The resistance of the conductor is ……………..
(a) 0.5Ω
(b) 2Ω
(c) 4Ω
(d) 20Ω
Answer:
(b) 2Ω

Question 2.
The resistance of a straight conductor is independent of …………………..
(a) temperature
(b) material
(c) cross sectional area
(d) shape of cross section
Answer:
(d) shape of cross section

Question 3.
Two resistances R1 and R2 are connected is parallel. Their equivalent resistance is


Answer:

Question 4.
If in the circuit, power dissipation is 150 W, then R is ……………..

(a) 2Ω
(b) 6Ω
(c) 5Ω
(d) 4Ω
Answer:
(b) 6Ω

Question 5.
The force between two parallel wires carrying currents has been used to define…………..
(a) ampere
(b) coulomb
(c) volt
(d) watt
Answer:
(a) ampere

Question 6.
Electric current passes through a metallic conductor due to the movement of ……………
(a) ions
(b) ampere
(c) electrons
(d) protons
Answer:
(c) electrons

Question 7.
What is the maximum resistance one can make with ten 1Ω resistors?
(a) 1Ω
(b) 2Ω
(c) 5Ω
(d) 10Ω
Answer:
(d) 10Ω

Question 8.
Two conductors of resistance 2 R and R are connected in series in a battery circuit. The ratio of heat developed In them is ……………………
(a) 2 : 1
(b) 1 : 2
(c) 1 : 3
(d) 1 : 4
Ans:
(a) 2 : 11

Question 9.
1 volt = …………..


Answer:

Question 10.
The resistance of a conductor is R. If Its length is doubled, then its new resistance will be ……………….
(a) R
(b) 2R
(c) 4R
(d) 8R
Answer:
(C) 4R

Question 11.
The following is not a safety device.
(a) Fuse
(b) Trip switch
(c) Ground connection
(d) Wire
Answer:
(d) wirel

Question 12.
In India the frequency of alternating current is,
(a) 220 Hz
(b) 50 Hz
(c) 5 Hz
(d) 100 Hz
Answer:
(b) 50 Hz

II. Fill in the blanks:

1. The number of electrons constituting 1-coulomb charge is………………….
Answer:
6.25 × 10¹⁸

2. Resistors are connected in series if the resistance of the electric circuit is to be………………….
Answer:
increased

3. Electric fuse is a wire made up of a material having ………………….melting point.
Answer:
low

4. ………………….is the only non-metal that is a good conductor of electricity.
Answer:
Graphite

5. If the area of cross section of the conductor is doubled its resistance gets ………………….
Answer:
halved

6. A negative charge will move from …………………. to …………………. potential.
Answer:
lower, higher

7. ………………….is work done per unit charge.
Answer:
Potential difference

8. An electrochemical cell converts …………………. energy into …………………. energy.
Answer:
chemical, electrical

9. Three resistors are connected in series with a cell. If the current in each resistor is 1.5A, then the current through the cell will be ………………….. Answer:
1.5A

10. Three resistors are connected in parallel with a battery. If the current in each resistor is 2A, then the current through the battery will be …………………..
Answer:
6A

11. As electrons are revolving in the ………………….of an atom they can be easily removed from an atom and also added to it.
Answer:
orbits

12. If an electron is added in excess to an atom then the atom is ………………….charged.
Answer:
negatively

13. The excess of electrons make an object negative and ………………….of electrons make it positive.
Answer:
deficit

14. Electric charge is ………………….in nature.
Answer:
additive

15. Electric lines of force are ………………….lines.
Answer:
imaginary

16. For an isolated positive charge the electric lines of force are radial…………………. and for an isolated negative charge they are radial…………………..
Answer:
outwards, inwards

17. ………………….at a point is a measure of force acting on a unit positive charge placed at that point.
Answer:
Electric field

18. Electric potential is a measure of the ………………….on the unit positive charge to bring it to that point against all electrical forces.
Answer:
work done

19. The movement of positive charge is called as ………………….
Answer:
conventional current

20. The …………………. is the measure of opposition offered by the component to the flow of electric current through it.
Answer:
resistance

21. The process of conduction of electric current through solution is called………………….
Answer:
electrolysis

22. The device used to convert AC to DC is called………………….
Answer:
rectifier

23. Trip switch is a …………………. safety device.
Answer:
electro mechanical

III. True or False:

1. A fuse is used in an electric circuit to stop high current flowing through the circuit.
Answer:
True.

2. Rheostat is also known as fixed resistance.
Answer:
False.
Correct statement: Rheostat is also known as a variable resistance.

3. An ammeter is always placed in parallel with the circuit.
Answer:
False.
Correct statement: An ammeter is always placed in series with the circuit.

4. The resistance of a dry human body is high.
Answer:
True.

5. For current to flow, one needs art open circuit.
Answer:
Correct statement: For current to flow, one needs a closed circuit.

6. A comb rubbed with hair and brought near pieces of paper attracts them, because both comb and paper get similarly charged.
Answer:
False.
Correct statement: A comb rubbed with hair and brought near pieces of paper attracts them, because both comb and paper get oppositely charged.

7. Overloading of electric circuits can lead to short-circuiting.
Answer:
True.

8. Electrons in outer orbits are called free electrons.
Answer:
True.

9. Electric fuse works on the Joule heating principle.
Answer:
True.

IV. Match the following:

I.

Column I	Column II
1. Resistor	a) Galvanometer
2. Connecting wire	b) Voltmeter
3. Current in an electric circuit	c) Copper
4. Potential difference	d) Constantan

Answer:
1-d, 2-c, 3 -a, 4-b

II.

Column I	Column II
1. Electric power	a) Volt
2. Electrical energy	b) Coulomb
3. Electric charge	c) Watt
c) Watt	d) Joule

Answer:
1-c, 2-d, 3-c, 4-a

V. Assertion and Reason type questions :

Mark the correct choice as :
(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 reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Question 1.
Assertion (A): Electric current will not flow between two charged bodies when connected if their charges are the same.
Reason (R): Current is the rate of flow of charge.
Answer:
(d) Assertion is false but the reason is true
Reason: Current will not flow when two bodies are at the same potential. When their charges are the same, their potential may be different. Hence current may flow in this case.

Question 2.
Assertion (A) : A bird perches on a high power line and nothing happens to the bird.
Reason (R) : The level of the bird is very high from the ground.
Answer:
(c) Assertion is true but reason is false
Reason: Electric shock is due to the electric current flowing through a living body. When the bird perches on a single high power line, no current passes through its body. Because its body is at an equipotent surface (i.e.) there is no potential difference. While when a man touches the same line, standing bare foot on the ground the electrical circuit is completed through the ground. The hands of man are at high potential and his feet are at low potential. Hence the large amount of current flows through the body of the man and the person, therefore, gets a fatal shock.

VI. Answer in one word:

Question 1.
Name the force which acts between two point charges obey Newton’s third law.
Answer:
Electrostatic force.

Question 2.
What is the SI unit for the current?
Answer:
ampere (A).

Question 3.
Name the device which is used to measure the strength of the electric current in an electric circuit.
Answer:
Ammeter.

Question 4.
What is the rate at which charges flow past a point on a circuit?
Answer:
Current.

Question 5.
Name a device that helps to maintain a potential difference across conductors.
Answer:
Cell or battery.

Question 6.
What does the circuit symbol represent?
Answer:
Wire crossing without touching each other.

Question 7.
How many electrons accumulate to make 1C of electric charge?
Answer:
1C = 6.25 × 10¹⁸ electrons.

Question 8.
What is the charge of one electron?
Answer:
e= 1.6 × 10^-19C.

Question 9.
What is the measure of the work done on the unit positive charge to bring it to that point against all electrical forces?
Answer:
Electric potential

Question 10.
How is a voltmeter connected in the circuit to measure the potential difference between two points?
Answer:
Parallel

VII. Subjective Problems:

Question 1.
Calculate the charge passing through a lamp in 2 minutes if the current is 3A.
Solution:
Current I = 3A
Time t = 2 minutes = 120seconds
Charge q = ?
q = I × t = 3 × 120
Charge q = 36.C

Question 2.
Calculate the current in a wire if a charge of 1500 coulomb flows through it in 5 minutes.
Solution:
Charge q = 1500 C
Time t = 5 minutes = 300 seconds
Current I =?
I = q/t = \(\frac{1500}{300}\)
Current I = 5A

Question 3.
A charge of 400C flows through a conductor for 13 minutes and 20 seconds. Find the magnitude of the current flowing through the conductor.
Answer:
Q = 400C
t = 13 min and 20s = 13 × 60 + 20
= 780 + 20
= 800s
Current I = \(\frac{Q}{t}=\frac{400}{800}=0.5 \mathrm{A}\)

Question 4.
10²⁰ electrons, each having a charge of 1.6 x 10^-19 C, flows in a circuit V is 0.1s. What is the current in ampere?
Solution :
n = 10²⁰ electrons
e = 1.6 × 10^-19C
t = 0.1s
Charge q = ne
= 10²⁰ × 1.6 × 10^-19
= 16C
Current I = \(\frac{q}{t}=\frac{16}{0.1}=160 \mathrm{~A}\)
∴ Current = 160 A

VIII. Long Answer Questions

Question 1.
a State Ohm’s law.
b. Draw a circuit diagram for the verification of ohm’s law. Also, plot graphically the variation of current with a potential difference.
Answer:
a. Ohm’s law states that the current passing through a conductor is directly proportional
to the potential difference a cross its ends, provided the physical conditions like temperature density etc. remain unchanged V ∝ I or V = IR.
b.

Question 2.
a. Why is series arrangement not used for domestic cricuits?
b. Explain why fuse wire is always connected in series arrangement.
c. Why are copper and aluminium wires useually employed for electricity transmission?
Answer:
a. Series arrangement is not used for domestic circuits because same current will flow through all the appliances. The equivalent resistance will get added and hence the current drawn by the circuit will be less.

b. Fuse wire is always connected in series in a circuit as it has to check the flow of current through the circuit and prevent the extra flow of current through it.

c. Fuse wire is always connected in series in a circuit as it has to check the flow of current through the circuit and prevent the extra flow of current through it.

Question 3.
Explain the dangers of electricity and precautions to be taken while handling electricity.
Answer:

• Damaged insulation – Do not touch the bare wire, use safety gloves, and stand on an insulating stool or rubber slippers while handling electricity.
• Overheating of cables – use quality ISI certified cable wires for domestic wiring
• Overload of power sockets – do not connect too many electrical devices to a single electrical socket.
• Inappropriate use of electrical appliances – always uses the electrical appliances according to the power rating of the device like AC point, TV point, microwave oven point, etc.
• Environment with moisture and dampness – keep the place where there is electricity out of moisture and wetness as it will lead to leakage of electric current.
• Beyond the reach of children – the electrical sockets are to be kept away from the reach of little children who do not know the dangers of electricity.

Question 4.
Write the difference between resistance in series and in parallel.
Answer:

IX.

Question 1.
Distinguish e.m.f and potential difference.
Answer:
As both e.m.f and potential difference are measured in volt, they may appear the same. But they are not. The e.m.f refers to the voltage developed across the terminals of an electrical source when it does not produce current in the circuit. Potential difference refers to the voltage developed between any two points (even across electrical devices) in an electric circuit when there is current in the circuit.

Question 2.
Some common symbols in the electrical circuit.
Answer:

Question 3.
Write a note on direct current.
Answer:

• Current in electrical circuits is due to the motion of positive charge from higher potential to lower potential or electron from lower to higher electrical potential.
• Electrons move from negative terminal of the battery to positive of the battery. Battery is used to maintain a potential difference between the two ends of the wire.
• Battery is one of the sources for dc current. The dc is due to the unidirectional flow of electric charges. Some other sources of dc are solar cells, thermocouples etc. The graph depicting the direct current is shown in Figure.
  
• Many electronic circuits use dc. Some examples of devices which work on dc are cell phones, radio, electric keyboard, electric vehicles etc.

Question 4.
Write a note on alternating current.
Answer:

• If the direction of the current in a resistor or in any other element changes its direction alternately, the current is called an alternating current.
• The alternating current varies sinusoidally with time. This variation is characterised by a term called as frequency.
• Frequency is the number of complete cycle of variation, gone through by the ac in
  one second. s
• In ac, the electrons do not flow in one direction because the potential of the terminals vary between high and low alternately.
• Thus, the electrons move to and fro in the wire carrying alternating current. It is diagrammatically represented in Figure

Question 5.
Explain the advantages of Ac over Dc.
Answer:

• The voltage of ac can be varied easily using a device called transformer. The ac can be carried over long distances using step-up transformers.
• The loss of energy while distributing current in the form of ac is negligible. Direct current cannot be transmitted as such.
• The ac can be easily converted into dc and generating ac is easier than dc
• The ac can produce electromagnetic induction which is useful in several ways.

X. Define the following:

1. Electric force: The force existing between the charges is called an ‘electric force’.
2. Electric potential: Electric potential is a measure of the work done on the unit positive charge to bring it to that point against all electrical forces.
3. Conventional current and electron current: The movement of the positive charge is called as ‘conventional current’. The flow of electrons is termed as ‘electron current’.
4. Current: Current is the rate at which charges flow past a point on a circuit.
5. Electromotive force (e.m.f.): The e.m.f of an electrical energy source is one volt if one joule of work is done by the source to drive one coulomb of charge completely around the circuit.
6. One ohm: One ohm is the resistance of a component when the potential difference of one volt applied across the component drives a current of one ampere through it.
7. Fixed resistor: A fixed resistor has a resistance of a fixed value. Common types of fixed resistors include carbon film resistors and wire-wound resistors.
8. Variable resistor: A variable resistor has a resistance that can be varied. It is used to vary the amount of current flowing in a circuit.
9. Electrolysis and electrolyte: The process of conduction of electric current through solutions is called ‘electrolysis’. The solution through which the electricity passes is called ‘electrolyte’.
10. Synaptic signals: Extremely weak electric current is produced in the human body by the movement of charged particles. These are called synaptic signals. These signals are produced by the electrochemical process. They travel between the brain and the organs through the nervous system.
11. Magnetic effect of current: A wire or a conductor carrying current develops a magnetic field perpendicular to the direction of the flow of current. This is called the magnetic effect of current.
12. Frequency: Frequency is the number of the complete cycle of variations, gone through by the ac in one second.
13. Rectifier: The device used to convert ac to dc is called a rectifier.
14. Resistance: The measure of opposition offered by the component to the flow of electric current through it.
15. Resistors: The components used for providing resistance are called resistors.

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 3 Fluids Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 3 Fluids

9th Science Guide Fluids Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
The size of an air bubble rising up in the water
(a) decreases
(b) increases
(c) remains the same
(d) may increase or decrease
Answer:
(b) increases

Question 2.
Clouds float in the atmosphere because of their low
(a) density
(b) pressure
(c) velocity
(d) mass
Answer:
(a) density

Question 3.
In a pressure cooker, the food is cooked faster because
(a) increased pressure lowers the boiling point.
(b) increased pressure raises the boiling point.
(c) decreased pressure raises the boiling point.
(d) increased pressure lowers the melting point.
Answer:
(b) increased pressure raises the boiling point

Question 4.
An empty plastic bottle closed with an airtight stopper is pushed down into a bucket filled with water. As the bottle is pushed down, there is an increasing force on the bottom. This is because
(a) more volume of liquid is displaced.
(b) more weight of liquid is displaced.
(c) pressure increases with depth.
(d) All the above.
Answer:
(c) pressure increases with depth

II. Fill in the blanks :

1. The weight of the body immersed in a liquid appears to be ………………… than its actual weight
Answer:
less

2. The instrument used to measure atmospheric pressure is …………
Answer:
Barometer

3. The magnitude of buoyant force acting on an object immersed in a liquid depends on ……………. of the liquid.
Answer:
density

4. A drinking straw works on the existence of ……………….
Answer:
atmospheric pressure

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

1. The weight of fluid displaced determines the buoyant force on an object.
Answer:
True.

2. The shape of an object helps to determine whether the object will float or not.
Answer:
False.
Correct statement: The density of an object helps to determine whether the object will floater sink.

3. The foundations of high-rise buildings are kept wide so that they may exert more pressure on the ground.
Answer:
False.
Correct statement: They may exert less pressure on the ground.

4. Archimedes’ principle can also be applied to gases.
Answer:
True.

5. Hydraulic press is used in the extraction of oil from oilseeds.
Answer:
True.

IV. Match the following :

Density	hpg
1 gwt	Milk
Pascal’s law	Pressure
Pressure exerted by a fluid	Mass/Volume
Lactometer	980 dyne

Answer:

Density	Mass/Volume
1 gwt	980 dyne
Pascal’s law	Pressure
Pressure exerted by a fluid	hpg
Lactometer	Milk

V. Answer in brief :

Question 1.
On what factors the pressure exerted by the liquid depends on?
Answer:
The pressure exerted by the liquid depends on the

• Depth
• Density of the liquid
• Acceleration due to gravity.

Question 2.
Why does a helium balloon float in the air?
Answer:
Helium is much less dense than ordinary air which gives them buoyancy and thus floats in the air.

Question 3.
Why it is easy to swim in river water than in seawater?
Answer:
The question itself is wrong. It is easier to swim in seawater than in the river water. It is because seawater has
(i) greater density and
(ii) larger buoyant force than river water.

Question 4.
What is meant by atmospheric pressure?
Answer:
The pressure exerted by the atmospheric gases on its surroundings and on the surface of the earth is called atmospheric pressure.

Question 5.
State Pascal’s law.
Answer:
Pascal’s law: The external pressure applied to an incompressible liquid is transmitted uniformly throughout the liquid.

VI. Answer in detail:

Question 1.
An appropriate illustration proves that the force acting on a smaller area exerts a greater pressure.
Answer:
Consider standing on loose sand. Your feet go deep into the sand. Now, when you lie down on the sand, you will find that your body will not go that deep into the sand. In both cases, the force exerted on the sand is the weight of your body which is the same. This force acting perpendicular to the surface is called thrust. When you stand on loose sand, the force is acting on an area equal to the area of your feet.

When you lie down, the same force acts on an area of your whole body, which is larger than the area of your feet. Therefore the effect of thrust, that is, the pressure depends on the area on which it acts. The effect of thrust on sand is larger while ‘ standing than lying.

Question 2.
Describe the construction and working of the mercury barometer.
Answer:

Mercury Barometer
1. It is designed by Torricelli.

Construction :
2. Mercury Barometer consists of long glass tube closed at one end and opened at the other.
3. Mercury filled through open end and close that end by thumb and open it after immersing it into a trough of mercury.

Working:
4. The Barometer works by balancing the mercury in the glass tube against the outside air pressure.
5. If air pressure increases, it pushes more of the mercury up into the tub.
6. If air pressure decreases, more mercury drains from the tub.
7. As vacuum cannot exert pressure, Mercury in the tube provides a precise measure of air pressure which is called atmospheric pressure.
8. It is used in a laboratory or weather station.

Question 3.
How does an object’s density determine whether the object will sink or float in water?
Answer:
Whether an object will sink or float in a liquid is determined by the density of the object compared to the density of the liquid. If the density of a substance is less than the density of the liquid it will float. For example, a piece of wood which is less dense than water will float on it. Any substance having more density than water (for example, a stone), will sink into the water.

Question 4.
Explain the construction and working of a hydrometer with a diagram.
Answer:

Purpose:
To measure density (or) relative density of the liquid.

Principle :
The weight of the liquid displaced by the immersed portion of the hydrometer is equal to the weight of the hydrometer. [Flotation principle].

Construction
Lower end of hydrometer :
A cylindrical stem having a spherical bulb which partially W Lead shots
filled with lead shots or mercury which helps to float or stand vertical in liquids.

Upper end of hydrometer:
A narrow tube has markings so that the relative density of liquids can be read off directly.

Working:

1. Liquid to be tested is poured into the glass jar.
2. The hydrometer is gently lowered into the liquid until it floats freely.
3. The reading against the level touching the tube gives the relative density of the liquid.

Question 5.
State the laws of flotation.
Answer:
Laws of flotation are

• The weight of a floating body in a fluid is equal to the weight of the fluid displaced by the body.
• The centre of gravity of the floating body and the centre of buoyancy are in the same vertical line.

VII. Assertion and Reason :

Mark the correct answer is:
(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 reason is not the correct explanation of assertion.
(c ) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Question 1.
Assertion (A) : To float, body must displace liquid whose weight is equal to the actual weight.
Reason (R): The body will experience no net downward force in that case.
Answer:
(a) Both assertion and reason are true and reason is the correct explanation of assertion]

Question 2.
Assertion (A) : Pascal’s law is the working principle of a hydraulic lift.
Reason (R): Pressure is thrust per unit area.
Answer:
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.]
Reason : Pascal’s law is the working principle of Hydraulic lift. In Hydraulic lift, applied pressure is transmitted uniformly and multiplied throughout the system.

VIII. Numerical Problems :

Question 1.
A block of wood of weight 200 g floats on the surface of water. If the volume of the block is 300 cm3, calculate the upthrust due to water.
Answer:
Weight of woodblock, m = 200 g
Volume of the woodblock, V = 300cm³
Upthrust = Weight of the fluid displaced = Volume of the woodblock
Upthrust = 300 cm³

Question 2.
Density of mercury is 13600 kg m^-3. Calculate the relative density.
Answer:
Density of Mercury = 13600 kg m^-3
Density of water at 4°C= 1000 kg m^-3

Question 3.
The density of water is 1 g cm^-3. What is its density in S.I. units?
Answer:
Density of water in SI units = 1000 kg / m³

Question 4.
Calculate the apparent weight of wood floating on water if it weighs 100g in air.
Answer:
Mass of wood = 100 g.
As the wood floats on the water, water will not be displaced.
So, the actual weight of wood is equal to the Apparent weight of wood.

IX. Higher Order Thinking Skills :

Question 1.
How high does the mercury barometer stand on a day when atmospheric pressure is 98.6 kPa?
Answer:
Pressure of Atmosphere PatnT = 98.6 kPa.
Density of Mercury, ρ_Hg = 13.6 × 10³ kg/cm³
Acceleration due to gravity, g = 9.8 m/s²

Question 2.
How does a fish manage to rise up and move down in the water?
Answer:

• Fish manages to rise up in the water by reducing its density by filling oxygen in the bladder via the gills. Thus volume will be increased to support its ascending motion.
• Fish moves down by decreasing its volume by releasing oxygen from the bladder. Thus volume will be decreased so it will sink in the water.

Question 3.
If you put one ice cube in a glass of water and another in a glass of alcohol, what would you observe? Explain your observations.
Answer:
Ice cube in water: As the density of ice cube is less than water, the ice cube floats in water.
Ice cube in alcohol: As the density of the ice cube is greater than alcohol, the ice cube will sink in alcohol.
Note: Density : Water = 1.00, Ice cube = 0.917, Alcohol = 0.78

Question 4.
Why does a boat with a hole in the bottom would eventually sink?
Answer:
A boat with a hole in the bottom eventually sinks due to :

• The water entered through a hole will increase the weight of the boat.
• The boat becomes heavier so it cannot displace more water. So the boat sinks.

Intex activities

ACTIVITY – 1

Stand on the loose stand. Your feet go deep into the sand. Now, lie down on the sand. What happens? You will find that your body will not go that deep into the sand. Why?

Aim:
To demonstrate the effect of thrust

Materials Required:
Sand

Procedure:

1. 1. First, you stand on the sand on your feet.
   2. Lie down on the sand with your whole body.

Observation:

1. While standing on your feet on sand, your feet go deep into the sand.
2. While lying down with your body on the sand, your body will not go deep into the sand.

Conclusion:

1. Pressure depends upon the area on which it acts.
2. The effect of thrust on sand is larger while standing than lying.

ACTIVITY – 2

Take a transparent plastic pipe. Also, take a balloon and tie it tightly over one end of the plastic pipe. Pour some water in the pipe from the top. What happens? The balloon tied at the bottom stretches and bulges out. It shows that the water poured in the pipe exerts pressure on the bottom of its container.

Aim: To demonstrate that water exerts pressure on the bottom of the container.

Materials Required: Plastic pipe, Balloon, Water.

Procedure :

1. Take a transparent plastic pipe and a balloon.
2. Tie the balloon tightly over one end of the plastic pipe.
3. Keep the pipe with the closed end at the bottom.
4. Pour some water in the pipe from the top.

Observation: The balloon tied at the bottom stretches and bulges out.

Conclusion: Water poured in the pipe exerts pressure on the bottom of its container.

[End of the activity]

ACTIVITY-3

Take a large plastic can. Punch holes with a nail in a vertical line on the side of the can as shown in the figure. Then fill the can with water. The water may just dribble out from the top hole, but with the increased speed at the bottom holes as depth causes the water to squirt out with more pressure.

Aim:
To demonstrate that pressure increases as depth increases.

Materials Required:

1. Large plastic can.
2. A sharp nail.

Procedure :

1. Take a large plastic can.
2. Punch holes with a nail in a vertical line up on the side of the can every inch or several centimeters.

Observation:

1. Water dribbles out from the top hole.
2. Water from the bottom hole flows with increased speed.

Conclusion:
Depth causes water to squirt out with more pressure.

ACTIVITY – 4

Take two liquids of different densities say water and oil to the same level in two plastic containers. Make holes in the two containers at the same level. What do you see? It can be seen that water is squirting out with more pressure than oil. This indicates that pressure depends on density of the liquid.

Aim :
To demonstrate pressure depends on the density of the liquid.

Materials Required:

1. Two plastic containers
2. Water
3. Oil (Both same volume)
4. Sharp nail

Procedure:

1. Take water and oil to the same level in two plastic containers.
2. Make a hole at the same level in two containers.

Observation:
Water squirts out with more pressure than that of oil.

Conclusion:
Pressure depends on the density of the liquid.

ACTIVITY – 5

Take two identical flasks and fill one flask with water to the 250 cm³ mark and the other with kerosene to the same 250 cm³ mark. Measure them in a balance. The flask filled with water will be heavier than the one filled with kerosene. Why? The answer is in finding the mass per unit volume of kerosene and water in respective flasks.

Aim :
To prove that the density of a substance is the mass per unit volume of a given substance.

Materials Required:

1. Two identical flasks.
2. Water
3. Kerosene (same volume as water)

Procedure :

1. Take two identical flasks.
2. Fill one flask with water to 250 cm³ mark.
3. Fill the other flask with kerosene to the same 250 cm³ mark.
4. Measure both flasks in balance separately.

Observation :
The flask filled with water will be heavier than that of the flask filled with kerosene.

Conclusion :

1. In the above activity, we know that Both water and kerosene have same volume (i.e.) 250 cm³.
2. The density of the water lg / cm³ and density of kerosene is 0.8g / cm³ mass
3. Density = \(\frac{\text { mass }}{\text { volume }}\), therefore mass = Density x volume
   Hence mass of water = 1g/cm³ x 250 cm³ = 250g
   mass of kerosene = 0.8 g / cm³ x 250 cm³ = 200g
4. Even though, water and kerosene have same volume, they have different densities. So water and kerosene have different masses.
5. Water has more mass than kerosene.
   Hence, we proved that the density of the substance is the mass per unit volume of the substance. [End of the activity]

9th Science Guide Fluids Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
Intermolecular forces are stronger in ………………
(a) gases
(b) liquids
(c) solids
(d) all the above
Answer:
(c) solids

Question 2.
Water (or) liquids exert pressure on
(a) Upward direction
(b) Downward direction
(c) Lateral direction
(d) All the above
Answer:
(d) All the above

Question 3.
The pressure does not depend upon
(a) Depth
(b) Area
(c) Density
(d) Acceleration due to gravity
Answer:
(b) Area

Question 4.
Fluids in general are
(a) Gases
(b) liquids
(c) Gases or Liquids
(d) None of these
Answer:
(c) Gases or Liquids

Question 5.
Scuba divers wear special suits to withstand
(a) Low pressure
(b) High pressure
(c) Low temperature
(d) High temperature
Answer:
(b) High pressure

Question 6.
To find out relative density of the substance, with respect to density of water……………C is taken.
(a) 4°
(b) 0°
(c) 100°
(d) 60°
Answer:
(a) 4°

Question 7.
Density Bottle is also called as
(a) Saccharometer
(b) Lactometer
(c) Pycnometer
(d) Barometer
Answer:
(c) Pycnometer

Question 8.
An object completely immersed in fluid displaces its own volume of fluid.
(a) Floatation principle
(b) Principle of buoyancy
(c) Pascal’s law
(d) Archimedes principle
Answer:
(d) Archimedes principle

Question 9.
A solid floats in liquid with a portion of it being submerged. Then
(a) The liquid exerts an upthrust equal to weight of the solid
(b) The weight of the dispersed liquid is equal to the weight of solid
(c) Solid exerts a force equal to its weight on liquid
Choose correct statements
(A) a & b
(B) a & c
(C) b & c
(D) All of these
Answer:
(A) a & b

Question 10.
The principle of “Hydrostatic balance” was devised by
(a) Torricelli
(b) Pascal
(c) Archimedes
(d) Newton
Answer:
(c) Archimedes

Question 11.
Saccharometer is used to measure the density of …………….in a liquid.
(a) Milk
(b) Sugar
(c) Alcohol
(d) Ether
Answer:
(b) Sugar

Question 12.
Most buoyant objects are those with relatively
(a) high volume
(b) higher mass
(c) low density
(d) less viscosity
(A) a & b (B) a & c (C) b & c (D) b&d
Answer:
(B) a & c

Question 13.
If there were no gravity, which of the following will not be there for fluid? (HOTS)
(a) Viscosity
(b) Density
(c) Pressure
(d) upthrust
Answer:
(d) upthrust

Question 14.
Human lung is well adopted to breath at a pressure of ………….kPa.
(a) 106.7
(b) 101.3
(c) 98.4
(d) 33.7
Answer:
(b) 101.3

Question 15.
Petroleum-based products float on the surface of the water. This is due to their low ………….
(a) volume
(b) density
(c) specific gravity
(d) viscosity
(A) a & b (B) a & c (C) a & d (D) b & c
Answer:
(D) b & c

II. Fill in the blanks :

1. It is easy to compress a gas whereas liquids are ………………….
Answer:
Incompressible

2. The net force in a particular direction is called ………………….
Answer:
Thrust

3. All flowing substances, both liquids, and gases are called ………………….
Answer:
Fluids

4. The air pressure at sea level is referred as ………………….
Answer:
Atmospheric pressure

5. The pressure in mines is ………………….than sea level.
Answer:
Greater

6. ………………….is the instrument used to measure the atmospheric pressure.
Answer:
Barometer

7. On each lm2 of surface, the force acting is ………………….
Answer:
1.013 kN

8. ………………….is a device for measuring atmospheric pressure without the use of liquids.
Answer:
Aneroid Barometer

9. Absolute Pressure is zero-referenced against a ………………….
Answer:
Perfect Vaccum

10. Psi stands for ………………….
Answer:
Pascal per inch

11. A tyre pressure of 30psi is almost ………………….the atmospheric pressure.
Answer:
Twice

12. The density of the substance is the …………………. of a given substance.
Answer:
mass per unit volume

13. Hydrometer is based on the principle of ………………….
Answer:
Flotation

14. The upward force that is caused due to the pressure difference in liquid (or fluid) is called ………………….
Answer:
Buoyant force

15. Hot air is ………………….dense than ordinary air.
Answer:
less

16. The Lactometer works on the principle of ………………….of milk.
Answer:
gravity

17. Icebergs and ships stay afloat due to ………………….
Answer:
Buoyancy

18. Archimedes principle is the consequence of ………………….
Answer:
Pascal’s law

19. The point in which the force of buoyancy is supposed to act is known as …………………..
Answer:
Centre of buoyancy

20. The centre of gravity of the floating body and the centre of buoyance are in the same ………………….line.
Answer:
Vertical

21. In a fluid, buoyant force exists because the pressure at the ………………….of an object is greater than the pressure at the top.
Answer:
bottom

III. Match the following :

(I)

1. Lactometer	a) Relative density
2. Saccharometer	b) Alcohol
3. Alcoholometer	c) Sugar
4. Pyncometer	d) Milk

Answer:
1. d
2. c
3. b
4. a

(II)

1.Hydraulic press	a) Archimedes
2.Cartesian Diver	b) Floatation
3. Hydrostatic Balance	c) Pascal’s law
4. Hydrometer	d) Buoyancy

Answer:
1. c
2. d
3. a
4. b

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

1. The shape and size of the solids do not easily change.
Answer:
True.

2. Liquid exerts pressure in the upward direction.
Answer:
False.
Correct statement: Liquid exerts pressure in all directions.

3. The barometer works by balancing the Mercury in the glass tube along with the outside air pressure.
Answer:
False.
Correct statement: The barometer works by balancing the Mercury in the glass tube against the outside air pressure.

4. The absolute pressure is zero-referenced against atmospheric pressure.
Answer:
False.

Correct statement: The absolute pressure is zero-referenced against a perfect vacuum.

5. The external pressure applied on an incompressible liquid is transmitted uniformly throughout the liquid.
Answer:
True.

6. The correct lactometer reading is only obtained at a temperature of 60° C.
Answer:
True.

7. If the buoyant force is less, the object will float.
Answer:
False.
Correct statement: If the buoyant force is less, the object will sink.

8. If the volume of object is above the water surface, then the object is less densed.
Answer:
True.

9. Upthrust = weight of the fluid displaced – apparent weight of the object.
Answer:
False.
Correct statement: Upthrust = Weight of the fluid displaced – apparent loss of weight of the object.

10. Salt water provides less buoyant force than freshwater.
Answer:
False.
Correct statement: Salt water provides more buoyant force than freshwater.

V. Very Short Answer Questions :

Question 1.
Differentiate Liquid from Gas.
Answer:
It is easy to compress a Gas. The liquid is Incompressible.

Question 2.
What is the SI unit of pressure?
Answer:
Newton per squaremeter (Nm^-2).

Question 3.
What are factors determining liquid pressure?
Answer:
(i) Depth (b) (ii) Density bf Liquid (□) (iii) Acceleration due to gravity (g).

Question 4.
Write the equation for pressure due to liquid column.
Answer:
P = hg ; P – Pressure, h- depth, p- density, g – Acceleration due to gravity.

Question 5.
What is referred to as atmospheric pressure?
Answer:
Air pressure at sea level is referred to as atmospheric pressure.

Question 6.
Expand the abbreviation ‘psi’.
Answer:
Psi = Pascal per inch.

Question 7.
What are Force multipliers?
Answer:
Hydraulic systems are known as-force multipliers.

Question 8.
Write the SI unit & symbol for density?
Answer:
SI unit = kilogram per meter cube (kg / m³).
Symbol = rho (ρ).

Question 9.
Where do we use lactometers?
Answer:
In milk processing units and Dairies.

VI. Answer in brief :

Question 1.
What happens when pressure is increased in solids?
Answer:
If the pressure is increased in solids

• it experiences tension
• it ultimately deforms (or) breaks.

Question 2.
How will you calculate fluid pressure?
Answer:

Question 3.
How will you find the absolute pressure?
Answer:

1. For pressures higher than atmospheric pressure:
   Absolute pressure = Atmospheric pressure + Gauge pressure.
2. For pressures lower than atmospheric pressure:
   Absolute pressure = Atmospheric pressure – Gauge pressure.

Question 4.
Why do Scuba divers wear special suits and equipment?
Answer:

1. Deep-sea has pressure twice that of atmospheric pressure.
2. At high pressure, parts of our body including blood vessels & soft tissues cannot withstand it.
   Hence they use special suits & equipment for protection.

Question 5.
Define Relative Density.
Answer:
Relative density of a substance is defined as ratio of density of substance to density of water at 4°C.

Question 6.
Name different types of Hydrometers with their applications.
Answer:

Name of Hydrometer	Application (measuring)
1. Lactometer	Density of milk
2. Saccharometer	Density of sugar in a liquid
3. Alcoholometer	Higher levels of alcohols in Spirits

Question 7.
What do you understand by the term “Buoyancy”.
Answer:
When a body partially or completely immersed in a liquid (fluid), the pressure is more at the bottom and less at the surface in the liquid.
This Pressure difference causes an upward force called “Buoyant force”. The phenomenon is called ‘Buoyancy’.

Question 8.
How do submarines sink and float in water?
Answer:
Submarines change the level of floating by pumping in and pumping out water into its compartments.

Question 9.
Differentiate positive & negative buoyant.
Answer:
Positive Buoyant

1. Weight of the object is less than the amount of water displaced.
2. More buoyant force
3. Object will float

Negative Buoyant :

1. Weight of the object is more than the amount of water displaced.
2. Less Buoyant force.
3. Object will sink.

Question 10.
You have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. In reality, one is heavier than the other. Can you say which one is heavier and why?
Answer:
The bag containing the iron bar is heavier than cotton.
Reason: Although both of them have the same weight, the bag of the iron bar has less volume so more dense compared to the bag of cotton which has more volume and less dense.

VII. Answer in detail :

Question 1.
Derive an expression for Pressure due to the Liquid column.
Answer:
A tall beaker filled with water to form a liquid column
Area of the cross-section at bottom = A
Height of liquid column = h
The density of the liquid = ρ
Thrust at bottom of liquid column (F) = Weight of liquid.
F = mg …(1) (∵ m – mass of liquid)
Mass,m = ρ × V ……………… (2)
Volume of liquid columñ, V = Area of cross-section (A) × height (h)
V = Ah ………….(3)
Substitute (3) in (2) n, = ρ Ah ………………… (4)
Substitute (4) in (1) F = ρ Ahg ……………….(5)
Pressure (P) = \(\frac{\text { Thrust (F) }}{\text { Area (A) }}=\frac{\rho \text { A h g }}{\mathrm{A}}\)
∴ P = hpg – This is the expression for pressure due to the liquid column.

Question 2.
Describe the construction and working of the Pycnometer.
Answer:
Pycnometer (Density Bottle)

Purpose: To measure relative density.

Construction :

1. Pycnometer consists of a ground glass stopper with a fine hole through it.
2. When the bottle is filled and the stopper is inserted, the excess liquid rises through the hole and runs down outside the bottle.

Working:

1. The bottle will always contain the same volume of liquid at a constant temperature.
2. The density of the given volume of substance to the density of equal volume of referred substance is called relative density or specific gravity of the substance.

Question 3.
Explain the Archimedes principle with an example.
Answer:
Principle:
A body immersed in a fluid experiences a vertical upward buoyant force equal to the fluid it displaces.

Explanation:
(1) When a body is partially or completely immersed in a fluid at rest, it experiences an upthrust which is equal to the weight of the fluid displaced by it.

(2) Due to the upthrust, the body loses a part of its weight equal to upthrust.
Upthrust = Weight of the fluid displaced.
= Apparent loss of weight of the body.
Apparent weight of an object = True weight of object in air – upthrust.

Question 4.
Describe the purpose, principle and working of Lactometer.
Answer:
Purpose: Lactometer is an instrument to check the purity of milk.
Principle: Gravity of milk.

Construction :

1. Lactometer consists of a long graduated test tube with a cylindrical bulb.
2. The cylindrical bulb has graduation from 15 at the top and 45 at the bottom, which filled with mercury.
3. The test tube is filled with water.
4. The air chamber causes the instrument to float.
5. Mercury causes lactometer to sink up proper level and to float in an upright position in the milk.
6. There is a thermometer inside the lactometer that extends to the upper part of test tube.

Working:

1. The correct lactometer reading is only obtained at 60°C.
2. Lactometer measures the cream (density) content of milk.
3. Lactometer floats in milk if milk has more cream content.
4. The average reading of normal milk is 32.

VIII. Numerical Problems :

Question 1.
A vessel with water is placed on a weighing pan and it reads 600 g. Now a ball of mass 40 g and density is 0.80g / cm3 is sunk into the water with a pin of negligible volume as shown in the figure. The weighing pan will show the reading of …………….?

Solution :
Weight of vessel with water = 600g
Mass of ball = 40g
Density of bal = 0.80 g / cm³
Volume of the ball = \(\frac{\text { mass }}{\text { density }}=\frac{40}{0.80}\)= 50g
So, weight of vessel + volume of ball = 600 + 50 g
The weighing pan will show = 650g
The weighing pan will show = 650g
The reading of a spring balance when a block is suspended from it in air is 60 newton. This reading is changed to 40 newton when the block is submerged in water. Calculate the specific gravity of block.
60 – 40 = 20 newton Weight of block in air
Loss of weight in water 60-newton / 20 newton = 3

Question 2.
The reading of a spring balance when a block is suspended from it in air is 60 newton. This reading is changed to 40 newtons when the block ¡s submerged in water. Calculate the specific gravity of block.
Solution:
Weight of block in air = 60 newton
Loss of weight of block in water = 60 – 40 = 20 newton

The specific gravity of block = 3

Question 3.
The mass of a body ¡s 4 kg and its volume is 500 cm³. Find its relative density.
Solution:
Massofthebodym = 4kg = 4000g
Volume ofthebodyv = 500 cm³

Question 4.
Calculate the pressure produced by a force of 800 N acting on an area of 2.0 m²
Solution :
Force = 800 N
Area = 2.0m²
Pressure, P =\(\frac{\text { Force }}{\text { Area }}=\frac{800}{2.0}\) = 400 Nm^-2
Pressure P = 400 Nm^-2 (or) 400 Pa

Question 5.
A swimming pool of width 9.0 m and length 24.0 m is filled with water of depth 3.0 m. Calculate the pressure on the bottom of the pool due to the water.
Solution:
Width of the pool, b = 9.0 m
Length of the pool, h = 24.0 m
Depth ofthepool,h = 3.0m
Density of water, p 1000 kg/m³
Pressure due to column of Fluid, P = ρhg
Acceleration due to gravity, g = 9.8 m/s²
Substituting the values, P = ρhg
P = 100kgm^-3 × (3.0m) × (9.8ms^-2)
Pressure, P = 29400kgm^-1s^-2      ∵1Pa = 1kgm^-1s^-2
∴P = 29400 Nm^-2 (or) 29400Pa

Question 6.
A body of volume 100 cc is immersed completely in the weight of water and the jar before immersion of the weight of water and jar after immersion.
Answer:
Volume of body completely immersed in water, V = = 100cc
Weight of water and jar before Immersion = 700g
The volume of jar immersed in water = Volume of water displaced = 100cc
Density of water = 1g/cm³
Mass of water displaced = Apparent weight loss
Mass of water displaced = Volume × density
= 100cc × 1g/cm³
Apparent weight loss of body = 100 g
Weight of jar and water after immersion = Weight of water and jar before immersion – Apparent weight loss
= 700g – 100g
= 600g.

IX. Assertion and Reason :

(a) Mark the correct choice as:
(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 reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Question 1.
Assertion (A) : The buoyant force on submerged rigid object can be considered to be acting at the centre of mass of object.
Reason (R) : In rigid body, force distributed uniformly through its volume can be considered to be acting at the centre of mass of the body.
Answer:
(c) Assertion is true but reason is false]
Reason : Centre of the mass of the body is fixed according to the distribution of density.

Question 2.
Assertion (A): The weight of the truck exerts less pressure on road.
Reason (R): The truck has six to eight wheels. As area increases pressure decreases.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 3.
Assertion (A): Air gets thinner with increasing altitude.
Reason (R): The atmospheric pressure increases as we go up in mountains.
Answer:
(c) Assertion is true but the reason is false
Reason: The atmospheric pressure decreases as we go up in mountains.

Question 4.
Assertion (A) : Lactometer is used to check the purity of milk.
Reason (R) : Lactometer measures the cream content of milk.
Answer:
(b) Both assertion and reason are true but the reason is not the correct explanation of the assertion
(b) Directions: In each of the following questions, a statement of Assertion (A) is given followed by a corresponding statement of Reason (R) just below it. Of the statements, mark the correct answer as :

Question 5.
Assertion (A) : The force acting on the surface of a liquid at rest, under gravity, in a container is always horizontal.
Reason (R) : The forces acting on a fluid at rest have to be normal to the surface.
Answer:
(d) Assertion is false but reason is true
Reason: The force acting on the surface of liquid at rest, under gravity, in a container is always perpendicular due to the fact that molecules at the surface is attracted by the molecules below the surface (i.e) an inward attraction.

Question 6.
Assertion (A): A sleeping mattress is so designed that when you lie on it, a large area of your body comes in its contact.
Reason (R) : This reduces the pressure on the body and sleeping becomes comfortable.
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion]

Question 7.
Assertion (A): Wide wooden sleepers are kept below railway lines to reduce pressure on the railway tracks and prevent them from sinking in the ground.
Reason (R): Pressure is directly proportional to the area in which it is acting.
Answer:
(c) Assertion is true but the reason is false
Reason: Pressure is inversely proportional to the area in which it is acting.

X. Define the following

1. Define thrust: The force which produces compression is called thrust. Its S.I units is newton
2. Define pressure: Thrust acting normally to a unit area of a surface is called pressure. Its S.I. Unit is the pascal.
3. Define atmospheric pressure: The pressure exerted by the atmospheric gases on its surroundings and on the surface of the earth is called atmospheric pressure. 1 atm is the pressure exerted by a vertical column of mercury of 76 cm height.
4. Buoyant force: The upward force experienced by a body when partly or fully immersed in a fluid is called upthrust or buoyant force.
5. Pascal’s law: Pascal’s law states that an increase in pressure at any point inside a liquid at rest is transmitted equally and without any change, in all directions to every other point in the liquid.
6. Archimedes principle: Archimedes’ principle states that when a body is partially or wholly immersed in a fluid, it experiences an up thrust or apparent loss of weight, which is equal to the weight of the fluid displaced by the immersed part of the body.
7. Density: Density is known as mass per unit volume of a body. Its S.I. unit is kg nr5.
8. Relative density: Relative density is the ratio between the density of a substance and the density of water. The relative density of a body is a pure number and has no unit.
9. Hydrometer: A hydrometer is a device used to measure the relative density of liquids based on Archimedes’ principle.
10. Lactometer: Lactometer is a device used to check the purity of milk by measuring its density using Archimedes’principle.

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf History Chapter 5 Migration Text Book Back Questions and Answers, Important Questions Notes.

Tamilnadu Samacheer Kalvi 9th Social Science Solutions Economics Chapter 5 Migration

Samacheer Kalvi 9th Social Science Migration Text Book Back Questions and Answers

I. Choose the correct Answer

Question 1.
According to the 2011 census, the total population of India was
(a) 121 crore
(b) 221 crore
(c) 102 crore
(d) 100 crore
Answer:
(a) 121 crore

Question 2.
_______ has recorded the maximum number of emigrants.
(a) Ramanathapuram
(b) Coimbatore
(c) Chennai
(d) vellore
Answer:
(c) Chennai

Question3.
during 2015,______of illiterates were migrants from Tamil Nadu.
(a) 7%
(b) 175%
(c) 23%
(d) 9%
Answer :
(a) 7%

Question4.
The poorer sections of the population migrate__________
(a) as a survival strategy
(b) to improve their living standards
(c) as a service
(d) to get experience
Answer:
(a) survival strategy

II. Fill in the blanks

1. Migration is enumerated on_______and_____bases.
2. The mobility of population in rural areas is ______than urban areas.
3. In rural india ,as per census 2011,________percent of the population are counted as migrants.
4. ______ is the major reason for female migration.
5. Any migrant stream would consist of______ sub streams.

Answer:

1. place of birth,place of residence
2. greater
3. 37
4. marriage
5. heterogeneous

III. Match the following

1. Migration policy – (a) Work
2. Female migrants – (b) low incidence of out migration
3. Chennai – (c) maximum number of emigration
4. Better off migrants – (d) marriage
5. Salem – (e) to reduce the volume of migration
6. Male migrants – (f) to improve the living standard

Answer:

1. – (e)
2. – (d)
3. – (c)
4. – (f)
5. – (b)
6. – (a)

IV.Give short answers

Question 1.
Enlist the reasons for migration.
Answer:
The reasons for migration include; Work/Employment, Business, Education, Marriage, and other such reasons.

Question 2.
What are the major factors responsible for female migrants in India?
Answer:

1. Among female migrants, 70 % in India and 51 % in Tamil Nadu report marriage as their reason for migration, in 2011.
2. Marriage and the movement associated with marriage appear to be a major factor responsible for women’s mobility in India and in Tamil Nadu

Question 3.
Name four districts in Tamil Nadu which record a low number of migration.
Answer:
Cuddalore, Karur, Thiruvannamalai, Vellore, Namakkal, Salem, Dindigul, Krishnagiri, Nilgiris and Dharmapuri districts record low number of emigrants.

Question 4.
What are the factors responsible for the poorer sections and better-off sections to migrate?
Answer:

1. Poorer sections of the population people migrate as a survival strategy.
2. Migrants from better-off sections move to their living standards.

Question 5.
List the four destinations and the percentage of migrants from Tamil Nadu.
Answer:
Of the total migrants who go to foreign countries, nearly 20% have chosen to go to Singapore, while 18% to the United Arab Emirates, 16% to Saudi Arabia, 13 % to the United States of America.

Question6.
What does the study reveal about the occupation undertaken by migrants?
Answer:

1. The study clearly reveals a whole range of occupations undertaken by migrants.
2. Highly skilled occupation on the one hand and low skilled occupations on the other with a large number of semi-skilled occupations in between.

V. Answer in detail

Question.1
State the aims of migration policies.
Answer:
Policies to address the problem of migration in developing countries like India essentially aim at the following:
To reduce the volume of migration: As a large part of the migration is a reflection of poverty
and insecurity faced by large sections of the rural people, the focus of intervention has to be in rural areas. Rural development policies to reduce poverty and insecurity would be essential to reduce the rate of migration.

To redirect the migrant streams: Redirection of migrant streams, away from big metropolitan cities is a desirable policy option. This policy can help in reducing spatial inequalities by suitable strategies, such as developing a more dispersed pattern of urbanisation.

Question.2
Discuss the patterns of migration.
Answer:

1. The pattern of migration is very complex, comprising of number of streams.
2. Rural to rural; rural to urban; urban to rural; urban to urban.
3. Short, medium and long distance migration streams.
4. Long-term stable migration and short-term circulatory type of movements.
5. Each of these streams would consist of different types of migrants (from different social classes), each with its own reason for migration.
6. The extent and nature of these rhigrant streams would essentially depend on.
   • Pressures and aspirations experienced hy people at the origin of migration.
   • Constraints imposed on mobility at the origin of migration.
   • Opportunities at the destination and
   • The cost of migration.

Question 3.
Elucidate about some of the interesting findings of migration in Tamil Nadu.
Answer:
In Tamil Nadu, two out of every five persons is reported to be a migrant in the year 2011. Incidence of migrants is higher in rural areas and larger among women. Tamil Nadu has a history of migration and people have moved for various reasons such as trade, business, employment etc, to various countries. During the colonial period, labourers had moved to other colonies seeking work and wages.

In the more recent period workers from Tamil Nadu have been moving to countries in the Gulf, the United States of America and Australia. In 2015, an independent research study was conducted to understand the level, nature and pattern of migration in Tamil Nadu. This study has made some interesting findings, as discussed below:

• Of the total migrants in Tamil Nadu, 65 percent have migrated or moved abroad while 35 percent have moved within the country.
• Chennai district has recorded the maximum number of emigrants followed by Coimbatore, Ramanathapuram and Tiruchirapalli districts.
  Cuddalore, Karur, Thiruvannamalai, Vellore, Namakkal, Salem, Dindigul, Krishnagiri, Nilgirfs and Dharmapuri districts record low number of emigrants. This study also provides information about the sex and destination of migrants Tamil Nadu.
• Of the total migrants who go to foreign countries, nearly 20% have chosen to go to Singapore, while 18% to the United Arab Emirates, 16% to Saudi Arabia, 13 % to the United States of America; and Malaysia, Kuwait, Oman, Qatar, Australia and England are also refered as important destinations for migrants from Tamil Nadu in the year 2015.
• Of the international migrants, 15 percent are women, while 85 percent are men.

Question 4.
Analyse the educational qualification of migrants from Tamil Nadu in 2015.
Answer:
On the question of educational qualifications of migrants from Tamil Nadu, the study reveals that in 2015 about 7 % were illiterates; 30 % have completed schooling ie. class 10; 10 % have completed class 12; 15 % had undergone some vocational training; 11 % were graduates; 12% were professionally qualified and 11 % had post graduate degrees.

VI. Write the correct statement.

Question 1.
In recent times workers from Tamil Nadu are moving to Africa.
Answer:
In the more recent period workers from Tamil Nadu have been moving to countries in the Gulf, United States of America and Australia.

Question 2.
In Tamil Nadu, the extent of migration is much higher in urban areas compared to rural areas.
Answer:
In Tamil Nadu, the extent of migration is much higher in rural are as compared to urban areas.

Question 3.
Any migrant stream would consist of homogenous sub-streams.
Answer:
Any migrant stream would consist of heterogenous-sub streams.

Question 4.
Two out of even, 10 persons are reported to be a migrant.
Answer:
Two out of every five persons are reported to be a migrant.

Samacheer Kalvi 9th Social Science Migration Additional Important Questions and Answers

I. Choose the correct Answer

Question 1.
In Tamil Nadu, migrants account for percent in rural areas.
(a) 38
(b) 41
(c) 28
(d) 50
Answer:
(b) 41

Question 2.
The driving force among men to migration is _________
(a) work
(b) employment
(c) tourism
(d) both a and b
Answer:
(d) both a and b

Question 3.
_________ Of the international migrants percent are women.
(a) 85
(b) 25
(c) 15
(d) 20
Answer:
(c) 15

Question 4.
Pick out the odd man _________
(a) Australia
(b) the USA
(c) Gulf countries
(d) Uganda
Answer:
(d) Uganda

II. Fill in the blanks.

1. During the colonial period, labourers had moved to other colonies seeking ______
2. Coimbatore has recored ______the number of emigrants next to Chennai.
3. _____is the difference in social status, wealth or opportunity between people or groups.
4. The process of moving from one place to another is known as ______
5. Change in populating occurs due to births, deaths and ______

Answer:

1. work and wages
2. maximum
3. Inequality
4. migration
5. migration

III. Match the following

1. Place of birth – (i) Paul Harris Daniel
2. Red Tea – (ii) Heterogeneous
3. Migration – (iii) Destination
4. Migrant stream – (iv) Lifetime migrant
5. Kuwait – (v) trade

Answer:

1.  – (iv)
2. – (i)
3. – (v)
4. – (ii)
5. – (iii)

IV.Give short answers

Question 1.
Mention the percentage of migrants in India as well as in Tamil Nadu.
Answer:

1. The percentage of migrants was 37 percent in the country.
2. It was at a much higher rate in Tamil Nadu at 43 percent.

Question 2.
How to determine the extent and nature of migration?
Answer:

1. The extent and nature of migration in any society is basically determined by the nature of the development process experienced by that society.
2. That is, the type and scale of development achieved by the agricultural and industrial sectors in an economy would determine the migratory patterns.

Question.3
What do the extent and nature of the migrant streams depend?
Answer:
The extent and nature of these migrant streams would essentially depend on:

1. Pressures and aspirations experienced by people at the origin of migration.
2. Constraints imposed on mobility at the origin of migration.
3. Opportunities at the destination and availability of information regarding these opportunities.
4. The cost of migration.

V.Answer in detail

Question 1.
Explain the concept of migration.
Answer:

1. In any settlement-village or town change in population occurs due to birth, death and migration.
2. Of these three components of population change, birth and death is clearly identifiable events while migration poses the maximum amount of problem with regards to its definition and measurement.
3. As almost everyone keeps moving most of the time, it is not easy to define which of these moves have to be classified as migratory moves.
4. In the Census of India, migration is enumerated on two bases – Place of birth and Place of residence.

Question 2.
Write a short note on “Red Tea”.
Answer:

1. “Red Tea” is a very well known novel written by Paul Harris Daniel.
2. The novel portraits the slavery life of plantation workers in Valparai.
3. This novel depicts the blood-stained history of the workers that is hidden behind the green cover of the hills.
4. This novel has been translated in Tamil by R. Murugavel in the name “Eriyum Panikkaadu” (6TifliL|LD usfilaafi
5. The story starts with Karupan migrating to the hills with his wife in search of survival.
6. The narrator of this story is Dr. Daniel, who comes there to treat the plantation employees.

VI. Write the correct statement

Question 1.
One usually associates mobility with female rather than male.
Answer:
One usually associate mobility with male rather than female.

Question 2.
Of the total migrants in Tamil Nadu, 65 percent have migrated toward rural areas.
Answer:
Of the total migrants in Tamil Nadu, 65 percent have migrated or moved abroad.

Question 3.
Work is the major factor responsible for female migrants in India.
Answer:
Work is the major factor responsible for male migrants in India.

Question 4.
Of the international migrants, 15 percent are men while 85 percent are women.
Answer:
Of the international migrants, 15 percent are women while 85 percent are men.

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf Economics Chapter 4 Tamilnadu Agriculture Text Book Back Questions and Answers, Important Questions Notes.

Tamilnadu Samacheer Kalvi 9th Social Science Solutions Economics Chapter 4 Tamilnadu Agriculture

Samacheer Kalvi 9th Social Science Tamilnadu Agriculture Text Book Back Questions and Answers

I. Choose the correct answer

Question 1.
Irrigated land surface out of cultivable land is __________
(a) 27%
(b) 57%
(c) 28%
(d) 49%
Answer:
(b) 57%

Question 2.
Out of the following which is not a food crop _________
a) Bajra
b) Ragi
c) Maize
(d) Coconut
Answer:
(d) Coconut

Question 3.
The productivity of paddy during the year 2014-2015
(a) 3,039 kg
(b) 4,429 kg
(c) 2,775 kg
(d) 3,519 kg
Answer:
(b) 4,429 kg

Question 4.
Both agricultural productivity and food productivity has ________
(a) decreased
(b) not stable
(c) remained stable
(d) increased
Answer:
(d) increased

Question 5.
The North-East monsoon period in Tamil Nadu
(a) August – October
(b) September – November
(c) October – December
(d) November – January
Answer:
(c) October-December

II. Fill in the blanks

1. The major occupation of people in Tamil Nadu is _________
2. Tamil Nadu receives rainfall all from the _________monsoon.
3. The total geographical area of Tamil Nadu is _________hectares.

Answer:

1. Agriculture
2. North-East
3. one crore 30 lakh and 33 thousand

III. Match the following

1. Non food crops – (i) 79,38,000
2. Dhal – (ii) less than hectare of cultivable land
3. North east monsoon – (iii) October – December
4. Small farmers – (iv) Urad Dal, Toor Dal, Green grams
5. No. of farmers in 2015 – 2016 – (v) Coconut, Channa

Answer:

1.  – (v)
2. – (iv)
3. – (iii)
4. – (ii)
5. – (i)

IV. Give short answers

Question 1.
Give two examples for each food crop and non-food crops.
Answer:
Example for food crops: Paddy, Maize Example for non-food crops: Coconut, Cotton.

Question 2.
What are the factors responsible for the changes in the cropping area?
Answer:
The size of the land, quality of the land, amount of rainfall received, reliable water source all contribute to a change in the cropping area.

Question 3.
Who monitors the quantity and quality of groundwater?
Answer:
The Union Ground Water Board is constantly monitoring the level and nature of groundwater. This continuous monitoring has categorized the Panchayat Union (blocks) in terms of the amount of groundwater used. 139 blocks in Tamilnadu are identified as excessive users of groundwater and 100 blocks as nearing the stage of excessive usage of groundwater. 11 blocks have been identified with reduced water quality. Only 136 blocks have enough quantity and quality water for usage.

Question 4.
On what factors does crop cultivation depend. List out the factors on which the crop cultivation depend.
Answer:
The crop cultivation depends on the amount of land being cultivated, the productivity of crops, source of water weather, rainfall etc.

Question 5.
Differentiate between small and marginal farmers.
Answer:

1. Marginal farmers cultivate is an area of less than one hectare.
2. Small farmers cultivate 1 – 2 hectares of land.
3. In Tamil Nadu, the number of marginal farmers is decreasing.

V. Answer in detail

Question 1.
Give a note on the water resources of Tamil Nadu.
Answer:
Northeast monsoon (Oct-Dec) is a major source of water for Tamil Nadu. The Northeast monsoon rains are stored in reservoirs, lakes, ponds, and wells for cultivation. Conventional water bodies like lakes, ponds and canals provide water for agriculture in Tamil Nadu. 2,239 canals run through Tamil Nadu covering a length of 9,750 km. There are 7,985 small lakes, 33,142 large lakes, 15 lakh open wells and there are 3,54,000 borewells in the state where agriculture is carried out with the help of these water resources.

The area of land that is irrigated using water from lakes is very low. Nearly 3.68 lakh hectares of land obtain water from lakes. The canals provide water to 6.68 lakh hectares. Borewells irrigate 4.93 lakh hectares and open wells provide water to 1L91 lakh hectares of land.

Question 2.
What are the problems faced by using groundwater for agriculture?
Answer:

1. Tamil Nadu agriculture is dependent on groundwater.
2. The use of groundwater for agriculture creates many hardships too.
3. There would be no suffering if the amount of water taken from the underground and the amount of water that goes into the underground during the rainy season are equal.
4. On the contrary, as the amount of water taken increases, the groundwater will go down resulting in complete dryness or change to unusable water.
5. The Union Water Board is constantly monitoring the level and nature of groundwater.
6. This continuous monitoring has categorized the Panchayat Union (Blocks) in terms of the amount of groundwater used.
7. 139 Blocks are identified as excessive users of groundwater and 100 Blocks identified as nearing the stage of excessive usage of groundwater.
8. blocks have been identified with reduced water quality. Only 136 blocks have enough quantity and quality of water for usage.
9. From this, we clearly understand that Tamil Nadu agriculture is dependent on groundwater. It is very urgent and necessary to regulate the usage of underground water. This is very important for fertile farming.

Question 3.
Discuss the source of irrigation for agriculture.
Answer:
There are no perennial rivers in Tamil Nadu. Tamil Nadu receives the required water from the Northeast and Southwest monsoons. When the southwest monsoon rains are high in the catchment areas of the Cauvery River in Karnataka dams get filled and in turn, the Cauvery river in Tamil Nadu gets water.

Northeast monsoon (Oct-Dec) is a major source of water for Tamil Nadu. The Northeast monsoon rains are’ stored in reservoirs, lakes, ponds, and wells for cultivation. Conventional water bodies like lakes, ponds, and canals provide water for agriculture in Tamil Nadu. 2,239 canals run through Tamil Nadu covering a length of 9,750 km. There are 7,985 small lakes, 33,142 large lakes, 15 lakh open wells and there are 3,54,000 borewells in the state where agriculture is carried out with the help of these water resources.

The area of land that is irrigated using water from lakes is very low. Nearly 3.68 lakh hectares of land obtain water from lakes. The canals provide water to 6.68 lakh hectares. Borewells irrigate 4.93 lakh hectares and open wells provide water to 11.91 lakh hectares of land.

Samacheer Kalvi 9th Social Science Tamilnadu Agriculture Additional Important Questions and Answers

I. Choose the correct answer

Question 1.
Cholam cultivation takes place in TamilNadu is __________
(a) 7% land area
(b) 1% land area
(c) 12% land area
(d) 9% land area
Answer:
(a) 7% land area

Question 2.
Krishi Karman award in related to __________
(a) cotton textile
(b) industrial growth
(c) food grain production
(d) educational growth
Answer:
(c) food grain production

Question 3.
Manila (groundnut) is grown in percent if the cultivated land.
(a) 6
(b) 3
(c) 10
(d) 12
Answer:
(a) 6

Question 4.
The third largest river in India __________
(a) Cauvery
(b) Godavari
(c) Krishna
(d) Mahanadhi
Answer:
(a) Cauvery

Question 5.
In 2011, nearly of the women were involved in agriculture __________
(a) 35%
(b) 55%
(c) 25%
(d) 45%
Answer:
(b) 55%

II. Fill the blanks

1. Most of the cultivations in Tamil Nadu are __________farmers
2. A major portion of the employee involved in agricultural activities are __________labourers.
3. In India the total land area under agriculture is __________fast.
4. If there is good water for a land, it can be cultivated more than __________in a year.
5. Nammaalvar believed in __________the’future generation of India.

Answer:

1. marginal
2. Landless
3. shrinking
4. one crop
5. youth

III. Match the following

1. Mettur Dam – (i) Tony Allen
2. Maize – (ii) Kallanai
3. Virtual water – (iii) Vanagam farm
4. Cauvery – (iv) Highest – storage
5. Nammaalvar – (v) Second

Answer:

1. – (iv)
2. – (v)
3. – (i)
4. – (ii)
5. – (iii)

IV. Give short answers

Question 1.
Write a note river Cauvery.
Answer:

1. River Cauvery is the third largest river in India. Its length is 765 km.
2. Cauvery passes Thiruchirapalli, Tanjavur, Srirangapattinam, Kumbakonnam.
3. The dams constructed across Cauvery in Tamil Nadu are Mettur Dam, Kallanai

Question 2.
What Is National Ayush Movement?
Answer:

1. The National Ayush Movement scheme is implemented by the central government.
2. Its main aim is to save and extend the life of many medicinal herbs that grow only in the forest.
3. This scheme is carried out with 60:40 shares from the central and state governments.

Question 3.
Write a note on Krlshi Karman award to TamllNadu.
Answer:

1. Tamil Nadu has the highest GDP in India according to 2017
2. Tamil Nadu tops in food grain production in 2015 – 2016 Prime Minister presented the Krishi Karman award to Tamil Nadu.
3. Mettur dam has the highest storage of water in Tamilnadu for agricultural Purpose.

Question 4.
Write a note on Farmer Producer Organizations (FPOs) in TamilNadu.
Answer:

1. Small and marginal farmers in Tamil Nadu will be benefited from FPOs.
2. Each of the producers’ groups have been given an investment grant of ?5 lakh to purchase farm equipment.
3. Apart from using the equipment within the group, these can also be rented out to other farmers.
4. The government also has a contract farming policy.

V. Answer in detail

Question 1.
Write about Nammaalvari journey towards Organic farming?
Answer:

1. When Green Revolution was spreading throughout the nation, Nammalvar started his life journey towards organic farming.
2. He resigned his regional Agricultural Developmental Officer post for this purpose.
3. He believed in the youth the future generation of India.
4. Nearly 6000 youth had completed training in organic farming in his Vanagam Farm.
5. He spent most of his days in struggles for organic farming and travels campaigning for the same.
6. He used only public transport.
7. He felt that this was his small role in reducing environmental pollution.

Question 2.
Explain the term Virtual water.
Answer:

1. The term virtual water was introduced by Tony Allen in 1990.
2. The water consumed in the production process of an agriculture or industrial product has been called the virtual water.
3. It is a hidden flow of water when food or other commodities are traded from one place to another..
4. For instance it takes 1340 cubic meters of water to produce one metric ton of wheat.
5. That is, if one metric ton of wheat is exported to another country, then, it means that 1340 cubic metre of water used to cultivate this amount of wheat is also being exported.
6. India is the largest global freshwater user.
7. India has been the fifth largest exporter of virtual water in the world.

Question 3.
Write a note on Micro Irrigation.
Answer:

1. Micro irrigation technology is a very good remedial to tackle shortage in irrigational water.
2. This irrigation technology helps to have a higher yield when compared to the traditional irrigational methods.
3. As only required amount of water is supplied at regular intervals, it increases the ability of water usage and productivity of the crop resulting in reduction of labour expenses and weed growth in the field.
4. The government has taken many measures to implement micro irrigation for proper distribution of water to crops that require more water.

Question 4.
What are Farmer Producer Organisations (FPOs)?
Answer:

1. In April 2013, the Government of India issued a National Policy and Process Guidelines on formation of FPOs.
2. The year 2014 was observed as the “Year of Farmer Producer Organisations” by the Government of India.
3. Its main idea of promoting and strengthening member based institutions of farmers.
4. It aimed at engaging the farmer companies to procure agricultural products and sell them.
5. Supply of inputs such as seed, fertilizer and machinery, market linkages, training & networking and financial and technical advice are also among the major activities of FPO

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf History Chapter 3 Money and Credit Text Book Back Questions and Answers, Important Questions Notes.

Tamilnadu Samacheer Kalvi 9th Social Science Solutions Economics Chapter 3 Money and Credit

Samacheer Kalvi 9th Social Science Money and Credit Text Book Back Questions and Answers

I. Choose the correct answer

1. Certain metals like ______ (gold/iron) were used as a medium of exchange in ancient times.
2. The Head Quarters of the RBI is at __________ (Chennai /Mumbai).
3. International trade is carried on in terms of ________ (US Dollars / Pounds).
4. The currency of Japan is ______ (Yen/Yuan)

Answer:

1. Gold
2. Mumbai
3. US Dollars
4. Yen

II. Fill in the blanks

1. ________ System can be considered as the first form of trade.
2. money supply is divided into _______.
3. The first printing press of the RBI was started at_________
4. ________act as a regulator of the circulation of money
5. the thesis about money by B.R. Ambedkar is _________

answer:

1. barter
2. four
3. nasik
4. reserve bank of india
5. the probiem of the rupee – its origin and solutio

III. Match the following:

1. US Dollar – (i) Automatic Teller Machine
2. Currency in circulation – (ii) Substitute of money
3. ATM – (iii) Universally accepted currency
4. Salt – (iv) Saudi Arabia
5. Riyal – (v) 85%

Answer:

1. – (iii)
2. – (v)
3. – (i)
4. – (ii)
5. – (iv)

IV. Give Short Answer

Question 1.
Why was money invented?
Answer:

1. If there were no money, we would be reduced to a barter economy.
2. In the market, we don’t barter for individual goods.
3. Instead, we exchange for goods (or) services for a common medium of exchange that is money.

Question 2.
What is ancient money?
Answer:

1. The metals can be termed as first form of currency.
2. Gold, Silver and Copper wefe the metals used first.
3. They were called ancient currency.

Question 3.
What were the items used as barter during olden days?
Answer:
Leather beads, shells, tobacco, salt, com, and even slaves were the items used as barter during the olden days.

Question 4.
What is spice route? Why was it called so?
Answer:

1. Spice route was an ancient trade route followed by merchants, importers and exporters.
2. The merchants followed spice routes of both land and sea from Malabar in India as far west as Morocco.
3. Pepper, Spices, Pearls, Gems, Rubies and Muslin clothes were exported from the eastern sea of Tamil Nadu.
4. Pepper and spices took a major share of the exports.
5. Thus this route was called the spice route.

Question 5.
What is natural money?
Answer:
The metals such as silver and gold gained importance gradually all over the world. So, these metals were used as a standard value in the exchange of goods. This was called natural money.

Question 6.
Why were coins of low value printed in large quantities?
Answer:

1. There were insufficient reserves of gold and silver.
2. Mines also had a limited reserve of these metals.
3. An alternative was found and coins were made using metals with lesser value.
4. These were used to buy and sell goods of lesser value.
5. It was used as the money of the poor people.

Question 7.
What is meant by foreign exchange?
Answer:

1. It is the conversion of one country’s currency into another. A country’s currency value may also be set by the country’s government.
2. It is a system of trading in and converting the currency of one country into that of another.

V. Answer in detail

Question 1.
Explain how money is transacted in the digital world.
Answer:

1. One has to visit the bank and fill in a challan or produce a cheque to withdraw money from his account.
2. Now this practice is gradually vanishing.
3. Instead, one can easily withdraw the necessary amount from an Automated Teller Machine (ATM), with the help of an ATM debit card.
4. One can easily withdraw the money needed at any time at ATMs located everywhere.
5. A person can deposit money in their account without visiting the branch.
6. Similarly, credit cards are also available, through which things are bought on credit and the amount can be paid later.
7. Now a days, instead of using cheques or Demand Drafts (DDs), online transactions through net banking are carried out.
8. Through this, money is transacted to anyone who lives anywhere across the globe.
9. Technology has advanced sci much that even mobile banking is widely used nowadays.

Question 2.
Explain in detail about the role of RBI in the country.
Answer:
A government has the responsibility to regulate money supply and oversee the monetary policy. Hoarding of money must be avoided at all costs in a country’s economy. Only then money can be saved in banks.

A major portion of the savings in banks are used for the development of industries, economic growth and various development schemes for the welfare of the poor.
All the major and important banks were nationalised (1969) in India. The Reserve Bank of India (RBI) regulates the circulation of currency in India.

The Reserve Bank of India started its operations on 1st April 1935. It was permanently moved to Mumbai from the year 1937. RBI was nationalised in 1949. 85% of the printed currency is let for circulation. According to the statistics available as on August 2018, currency worth of 19 lakh crore are in circulation.

Question 3.
Write in detail about the various functions of money.
Answer:

1. When money replaced the barter system, a lot of practical issues were solved.
2. Money acts a medium of exchange, a unit of measurement, a store in value and a standard of deferred payments.
3. plays an important role in transactions.
4. Medium of Exchange – Money should be accepted liberally in exchange of goods and services in a country.
5. Unit of Account – Money should be the common, standard unit of calculating a country’s total consumer goods, products, services etc. For example, if a book costs 50, it means that the price of the book is equal to 50 units of money. Money is used to measure and record financial transactions in a country.
6. A Store of Value – Money is used as a store of purchasing power. It can be used to finance future payments.

VI. Write the correct statement

Question (a)

1. The barter system flourished wherever civilizations thrived.
2. This was the initial form of trade.

(i) 1 is correct; 2 is wrong
(ii) Both 1 and 2 are correct
(iii) Both 1 and 2 are wrong
(iv) 1 is wrong; 2 is correct
Answer:
(ii) Both 1 and 2 are correct

Question (b)

1. Most of the international trade transactions are carried out in US dollars.
2. No other country except the US carries out trade in the world.

(i) Both the statements are correct.
(ii) Both the statements are wrong.
(iii) 1 is correct; 2 is wrong
(iv) 1 is wrong; 2 is correct
Answer:
(iii) 1 is correct; 2 is wrong

VII. Project and Activity

Question 1.
Visit a local museum and collect information about the coins displayed there.
Answer:
Activity to be done by the students themselves

Question 2.
Imagine you are going abroad for a Post Graduation course in architecture. Write a letter to the Branch Manager regarding an education loan.
Answer:
Date: 12th June 20xx.
From
xxxx yyyy
Chennai – 600 xxx.
To
The Branch Manager,
State Bank of India, xxx Branch,
Chennai – 600 xxx
Sir,
Sub: Request to sanction Educational Loan

I submit the following for your kind perusal.

I have completed my B.Arch. degree in Anna University. I have applied for a Post graduation course in architecture, that is, M. Arch at Kingston University in Australia. I have got the admission card also. But the cost of studies is too high. I request you to kindly sanction an educational loan for Rs.8 lakhs.

I am an account holder of your bank here. My SB Account No. is xxxx xxxx xxxxx.

I will be much obliged if you kindly consider my application and sanction the Educational Loan. Expecting your favourable reply.

Thanking you.
Yours faithfully,
[Signature]

VIII. Life Skills

Question 1.
Observe at a 20 rupee note. What is written on it?
Answer:
The following lines are written on it in Hindi and English.
Reserve Bank of India.
Guaranteed by the Central Government.
I promise to pay the bearer the sum of twenty rupees.
(Singend)
Governor

Question 2.
Prepare a family budget for a month.
Answer:
Activity to be done by the students themselves based on the monthly income.

Intext HOTS

Question 1.
How important is foreign exchange to one’s country?
Answer:
The foreign exchange market is merely a part of the money market in the financial centres. The buyers and sellers of claim on foreign money and the intermediaries together constitute a foreign exchange market. It is not restricted to any given country or geographical area.

There is a wide variety of dealers in the foreign exchange market. Banks dealing in foreign exchange have branches with substantial balances in different countries. Through their branches and correspondents, the services of such banks, usually called “Exchange Banks,” are available all over the world.

Samacheer Kalvi 9th Social Science Money and Credit Additional Important Questions and Answers

I. Choose the correct answer

1. Barter system involved the exchange of ______ (Goods/Money)
2. NFC was introduced in Britain in the year ______ (2016/2008)
3. The Chinese made coins out of ______ (Bronze/Copper)
4. In 1999 mobile banks were used in ______ (USA/Europe)
5. In educational loans the ______
6. One rupee and two rupee notes were first printed in India in the year ______ (1917/1927)
7. Security Priting and Minting Corporation of India Ltd. was started in ________(Mumbai/Dewas)

Answer:

1. Goods
2. 2008
3. Bronze
4. Europe
5. Student
6. 1917
7. Dewas

II. Fill in the blanks

1. Exchange of goods means _____
2. Countries bordering the Indian ocean used ______
3. Paper money spread to Europe through the travels of __________
4. A gold plated coin called the was introduced in Europe __________
5. The Credit card was invented by __________
6. In 2016 NFC got introduced in __________
7. All the major and important banks were nationalised in India in __________
8. There is no security required for the loan amount upto _________
9. The relationship between money and price is connected with the policy __________
10. Trades and small entrepreneurs need for their needs __________
11. When the metal supply got limited 2 currency was introduced __________
12. The medium of exchange in a country is __________

Answer:

1. Barter System
2. Shells
3. Marco Polo
4. Florin
5. John Biggins
6. India
7. 1969
8. 4 lakhs
9. Monetary
10. Credit
11. Paper
12. currency

III. Match the following

Question 1.

1. European union – (i) Pound
2. England – (ii) Ringgit
3. China – (iii) Dollar
4. Malaysia – (iv) Euro
5. Australia – (v) Yuan

Answer:

1. – (iv)
2. – (i)
3. – (v)
4. – (ii)
5. – (iii)

IV. Give short answers

Question 1.
What is ATM?
Answer:

1. ATM means Automated Teller Machine, with the help of an ATM debit card.
2. One can easily withdraw the money needed at any time at ATMs located everywhere.

Question 2.
How is the major portion of the savings in banks used?
Answer:
A major portion of the savings in banks are used for the development of industries, economic growth and various development schemes for the welfare of the poor.

Question 3.
What phenomenon increased the importance of the market and money?
Answer:

1. Growing crops and production are done on a commercial basis, rather than on a subsistence level.
2. This phenomenon also increased the importance of the market and money.

Question 4.
What type of currency notes was available till 1947?
Answer:

1. Till 1947, the currency notes with the image of King George VI were in circulation.
2. After Independence, the Government of India issued currency notes.

Question 5.
Why do we say that money, a store of value?
Answer:

1. Money is used as a store of purchasing power.
2. It can be used to finance future payments.

Question 6.
What is meany by SHG?
Answer:
People who live in a particular place or those who are involved in a certain work join together as a group and start saving. These are called Self Help Groups (SHG).

V. Answer in detail

Question 1.
What are educational loans?
Answer:

1. Educational loan attempts to meet the educational aspirations of the society.
2. A student is the main borrower.
3. A parent, spouse, or sibling can be the co-applicant.
4. It is offered to students who want to pursue higher education in India or overseas.
5. It can be taken for a full-time, part-time or vocational course, and Graduation or Post Graduation.
6. There is no security required for the loan amount up to 4 lakhs
7. The loan is repaid by the student generally after the employment.
8. Students can apply through “Vidya Lakshmi Portal Education Loan Scheme”

Question 2.
Explain the relationship between Money and Price.
Answer:

1. The relationship between money and price is connected with the Monetary policy.
2. There is a close relationship between the growth of money supply and inflation.
3. Price controls play a very important role in a country’s economic stability.
4. This role is played by RBI.
5. Currency is the medium of exchange in a country.
6. The Indian currency is called the Indian Rupee (INR).
7. In a country the foreign currency is called foreign exchange.
8. Purchasing capacity of all currencies in the world are compared using the US dollar as the standard currency.
9. This value differs from country to country.
10. Most of the international trade transactions are carried out in US dollar.

Question 3.
How is currency printed in India?
Answer:

1. In 1925, the British government established a government press at Nasik in Maharashtra
2. Currencies were printed three years later.
3. In 1974, a press was started in Dewas, Madhya Pradesh.
4. In the 1990’s two more presses were started in Mysuru, Karnataka, and Salboni in West Bengal to print bank notes.
5. The Reserve Bank of India has the authority to decide the value of currency to be printed and how the amount should reach its destination safely.
6. Though the RBI has the power to print up to ten thousand rupee notes, at present a maximum of upto rupees two thousand is printed.

Question 4.
Write a note on credit.
Answer:

1. Farmers avail credit during monsoons for buying seeds, agricultural input and other expenses.
2. Traders and small entrepreneurs need credit for their needs.
3. Even large industries receive a credit to take up their new projects.
4. Credit is available from:
   • Formal financial institutions like nationalised and private banks and co-operative banks
   • Informal financial institutions
   • Micro credit is received through Self Help Groups (SHG).
5. As far as nationalised banks and co-operative banks are concerned the interest to credit is comparatively lesser and there is a guarantee for the pledged, goods.

Question 5.
What is an informal financial institution?
Answer:

1. Informal financial institutions are easily approachable to customers with flexible procedures.
2. But there are issues like the safety of items pledged high rates of interest and modes of recovery.
3. The nationalised banks provide help to these groups through micro-credit.
4. Credit is given through SHG for street vendors, fishermen, especially women, and the poor.
5. In Tamil Nadu, all the banks have 10,612 branches, across the state.

Question 6.
Why is foreign exchange important?
Answer:

1. Without the ability to trade in different currencies, companies’ prospects would be limited.
2. As a result, global economic growth would suffer.
3. Investors also use the forex market.
4. Those who seek international diversification benefits need to trade currencies to buy and sell foreign assets and securities.
5. Foreign exchange reserve increases the confidence in the monetary and exchange rate policies of the government.
6. Foreign exchange reserves come to the rescue of any country to absorb the distress related to such a crisis.
7. In doing so the foreign exchange market is the mechanism that transfers purchasing power from one country to another.

VI. Write the correct statement

Question 1.
1. Mobile banking is not used.
2. Pepper and Spices took a major share of exports.
(i) Both 1 and 2 are correct
(ii) Both 1 and 2 are wrong
(iii) 1 is correct, 2 is wrong
(iv) 1 is wrong, 2 is correct
Answer:
(iv) 1 is wrong, 2 is correct

Question 2.
1. Reserve Bank of India was permanently moved to Mumbai from 1935
2. Gold, silver and copper were called ancient money.
(i) Both 1 and 2 are correct
(ii) 1 is correct, 2 is wrong
(iii) 1 is wrong, 2 is correct
(iv) Both 1 and 2 are wrong
Answer:
(iii) 1 is wrong, 2 is correct

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf Economics Chapter 2 Employment in India and Tamilnadu Text Book Back Questions and Answers, Important Questions Notes.

Tamilnadu Samacheer Kalvi 9th Social Science Solutions Economics Chapter 2 Employment in India and Tamilnadu

Samacheer Kalvi 9th Social Science Employment in India and Tamilnadu Text Book Back Questions and Answers

I. Choose the correct answer

Question 1.
We take age group ______ years for computation of the workforce.
(a) 12 – 60
(b) 15 – 60
(c) 21 – 65
(d) 5 – 14
Answer:
(b) 15 – 60

Question 2.
Which is the correct sequence of various sectors in GDP of India in the descending order?
(a) Primary sector, Secondary sector, Tertiary sector
(b) Primary sector, Tertiary sector, Secondary sector
(c) Tertiary sector, Secondary sector, Primary sector
(d) Secondary sector, Tertiary sector, Primary sector
Answer:
(c) Tertiary sector, Secondary sector, Primary sector

Question 3.
Which one of the following sectors is the largest employer in India?
(a) Primary Sector
(b) Secondary Sector
(c) Tertiary Sector
(d) Public sector
Answer:
(a) Primary Sector

Question 4.
Which one of the following is not in Primary Sector?
(a) Agriculture
(b) Manufacturing
(c) Mining
(d) fishery
Answer:
(a) manufacturing

Question 5.
Which one of the following is not in the Secondary Sector?
(a) Construction
(b) manufacturin
(c) Small Scale Industry
(d) forestry
Answer:
(a) Forestry

Question 6.
Tertiary Sector include/s
(a) Transport
(b) insurance
(c) banking
(d) all of these
Answer:
(a) all of these

Question 7.
Which sector is not included in the occupational pattern?
(a) Primary sector
(b) Secondary sector
(c) Tertiary sector
(d) Private sector
answer :
(a)private sector

Question 8.
Match List I with List II using the codes given below:

(1) Agriculture, Forestry, Fishery and Mining – a. Unorganised sector
(2) Manufacturing, Electricity, Gas and Water Supply – b. Service Sector
(3) Trade, Transport and Communication – c. Secondary sector
(4) Unincorporated Enterprises and Household industries – d. Primary Sector
Answers:
1. (d)
2. (c)
3. (b)
4. (a)

Question 9.
Which Delhi Sultan of medieval India formed ‘Employment Bureau’ to solve the unemployment problem.
(a) Muhamad Bin Tugluq
(b) Allauddin Khilji
(c) Feroz Shah Tugluq
(d) Balban
Answer:
(d ) Feroz Shah Tugluq

Question 10.
_____sector is registered and follows government rules.
(a) Agriculture
(b) Organised
(c) Unorganised
(d)private
answer:
(b)organised

Question 11.
_______sector provides job security and higher wages.
(a) Public sector
(b) Organised sector
(c) Unorganised sector
(d) Private sector
answer :
(b) organised sector

Question 12.
Find the odd one
(a)banking
(b) Railways
(c)insurance
(d) Small Scale Industry
Answer:
(d) Small Scale Industry

Question 13.
The sectors are classified into Public and Private sectors on the basis of
(a) number of workers employed
(b) nature of the economic activity
(c) ownership of enterprises
(d) employment conditions
Answer :
(c) ownership of enterprises

Question 14
Assertion (A): The unorganised sector of the economy characterised by household manufacturing activity and small-scale industry.
Reason (R): Jobs here are low paid and often not regular
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true and (R) does not explain (A)
(c) (A) is correct and (R) is false
(d) (A) is false and (R) is true
answer:
(b) Both (A) and (R) are true and (R) does not explain (A)]

Question 15.
People who employ workers and pay rewards for their work is termed as
(a) employee
(b) employer
(c) labour
(d) caretaker
Answer:
(b) employer

Question 16.
_____ continues to be the largest employer in Tamil Nadu.
(a) Agriculture
(b) Manufacturing
(c) Banking
(d) Small Scale Industry
Answer:
(a) Agriculture

II. Fill in the blanks

1. In _____ sector, the employment terms are not fixed and regular
2. Economic activities are classified into_____ and____ sectors.
3. _____ has always featured as an important element of development policy in India.
4. Employment pattern changes due to_________
5. The nature of employment in India is__________
6. _______of the economy is the number of people in the country, who work and also capable of working
7. public sector means________

Answer:

1. unorganised
2. public, private
3. employment
4. the lifestyle of the people
5. multi-dimensional
6. labour force
7. government undertaking

III. Match the following

1. Public sector – a. Banking
2. Private sector – b. Poultry
3. Primary sector – c. Profit motive
4. Tertiary sector – d. Service motive

Answer:

1. – (d)
2. – (c)
3. – (b)
4. – (a)

IV. Give Short answers

Question 1.
What is labour force of the economy?
Answer:
Labour force of the economy is the number of people in the country who work and also capable of working.

Question 2.
Why are children and old age (above 60 years) are not considered for the computation of the workforce?
Answer:

1. Persons less than 15 years are considered as children.
2. Persons above 60 years of age are excluded as they are not physically fit to take productive
   occupation
3. If larger percentage of population is accounted for by children and old age persons, then the progress of the country would be very slow as the working force is very small.

Question 3.
What are the three sectors of an economy?
Answer:
The economy is classified into three sectors. Primary (or) Agriculture sector, Secondary (or) Industrial sector, and Tertiary (or) Service sector.

Question 4.
Agriculture, despite a sharp decline in Gross Domestic Product, continues to be the largest employer in Tamil Nadu. Give reason.
Answer:

1. Agriculture despite a sharp decline in Gross Domestic Product continues to be the largest employer in Tamil Nadu.
2. This is because the Non – agriculture sectors have not generated enough employment to affect a shift of labour force.

V. Answer in detail

Question 1.
Explain: (a) primary sector; (b) secondary sector; (c) tertiary sector.
Answer:
The structure of employment denotes the number of workers engaged in different sectors of the economy.

Primary Sector: Agriculture, forestry, animal husbandry, poultry, dairy farming, fishing, etc.

Secondary Section: Manufacturing, small and large scale industries, and constructional activities.

Tertiary Sector: Transport insurance banking, trade, communication, real estate, government, and non-government services.
In developing countries like India that a large workforce will be engaged in the Primary Sector, while a small proportion in Secondary and Tertiary sectors.

Question 2.
Explain the employment structure of India.
Answer:

1. The nature of employment in India is multi-dimensional.
2. Some get employment throughout the year, some others get employed for only a few months in a year.
3. The economy is classified into three sectors. Primary or agricultural sector, secondary or industrial sector, tertiary or service sectors.
   • Primary Sector – Agriculture, animal husbandry, poultry, dairy farming etc.
   • Secondary Sector – Manufacturing, small and large scale industries and constructional activities.
   • Tertiary Sector – Transport, Insurance, Banking, Trade, Communication, Government and Non-government.
4. In developing countries like India, large workforce will be engaged in primary sector while a small proportion in secondary and tertiary sectors.
5. Employment growth in India has however not been adequate in view of faster growth in recent years.
6. Employment has always featured as an important element of development policy in India.
7. Employment growth has increased at an average rate of 2% during the past four decades since 1972-1973.

Question 3.
Compare the employment conditions prevailing in the organised and unorganised sectors
Answer:
Organised Sector:

1. It is incorporated with the appropriate authority or government with specific rules and regulations.
2. The employers in the sectors are provided with job security and receive higher wages than those of the unorganised sectors.
3. Employees of Central and State government, Banks, Railways, Insurance, Industry are called orgasnised sector.
4. They have fixed working hours, good salary, paid holidays and provides medical allowance and Insurance also.

Unorganised Sector:

1. It is characteristic the household manufacturing activity and small-scale industry without proper rules and regulations.
2. Employment is not secure, when there is no work, people are asked to leave the job.
3. This sector includes a large number of people who are employed on their own doing small jobs such as selling on the street, doing repair work and so on.
4. The employment terms are not fixed and regular. They do not enjoy any special benefit or job security. These enterprises are not registered with the government.

Question 4.
Distinguish between the Public sector and the Private sector.
Answer:
Public Sector:

1. Service motive.
2. The government owns the assets.
3. Wages are paid by Government.
4. Preserves national wealth.
5. Eg: NLC, SAIL, BSNL

Private Sector:

1. Profit motive.
2. Private individuals own the assets.
3. Wages are paid by the owner of Private enterprises.
4. Exploitation of natural resources like forest, mines for their personal benefit.
5. Eg: TVS Motors, Ashok Leylnd, TATA steel.

VI. Projects and Activities

Question 1.
Make a long list of all kinds of work that you find adults around you. In what way can you classify them?
Answer:

• Agriculture, Food & Natural resources.
• Business, Management & Administration.
• Communication & Information Systems.
• Engineering, Manufacturing & Technology.
• Health Science Technology.
• Human Services.

Question 2.
A research scholar looked at the working people in the city of Chennai and found the following
Answer:

Place of work	Nature of employment	Percentage of working people
In offices and factories registered with the government.	Organised	15
Own shops, offices, clinics in marketplaces with a formal licenses.		20
People working on the street, construction workers, domestic workers.		25
Working in small workshops usually not registered with the government.

Answer:

Place of work	Nature of employment	Percentage of working people
In offices and factories registered with the government.	Organised	15
Own shops, offices, clinics in marketplaces with a formal licenses.	Private	20
People working on the street, construction workers, domestic workers.	Unorganised	25
Working in small workshops usually not registered with the government.	Unorganised

Question 3.
Classify the following list of occupations under primary, secondary, and tertiary sectors. Milk vendor, tailor, teacher, doctor, farmer, postman, engineer, potter, fisherman, artisans, policeman, banker, driver, carpenter.
Answer:

Primary	Secondary	Tertiary
Farmer	Engineer	Doctor, Policeman,
Fisherman	Potter	Postman
	Carpenter	Banker
	Artist	Teacher

VII. HOTS

Question 1.
the tertiary sector is in top position in the world now justify.
Answer:

1. In a direct sense, the tertiary sector is mostly independent.
2. This sector primarily includes those activities that help in the development of the primary and secondary sectors.
3. They aid and support the production process.
   e.g., The transport sector, that uses trucks to transport finished products from factory to the retail stores.
4. The service sector also includes some essential services that may not directly help in the production of goods.
   e.g., Teachers, doctors, washermen, barbers, etc.
5. The tertiary sector actually caters to the excess income in a person’s hand after he is successful in acquiring his basic needs. This sector will remain a chief engine for future growth.

VIII. Life Skill

Question 1.
Discuss the sectors of your village economy.
Answer:

1. The teacher will make the students gain knowledge of the Primary, Secondary, and Tertiary sectors.
2. The students will be asked to collect information regarding the three sectors.
3. The students will be advised to classify the jobs available under the Primary, Secondary, and Tertiary sectors in their village.

Samacheer Kalvi 9th Social Science Employment in India and Tamilnadu Additional Important Questions and Answers

I. Choose the correct answer

Question 1.
In India the nature of employment in India is _______
(a) agriculture-oriented
(b) industry-oriented
(c) skill-oriented
(d) multi-dimensional
Answer:
(d) multi-dimensional

Question 2.
The organised sector provides _________
(a) good salary
(b) medical allowance
(c) paid holidays
(d) all the three
Answer:
(d) all the three

Question 3.
Government plays a major role in sector _________
(a) agricultural
(b) private
(c) Public
(d) unorganised
Answer:
(c) Public

Question 4.
Iruvelpattu is a village in _________
(a) Erode
(b) Chengelpet
(c) Villupuram
(d) Vellore
Answer:
(c) Villupuram

II. Fill in the blanks.

1. Those who are engaged in economic activities are called _________
2. In well-developed countries, the proportion of workforce engaged in agriculture will be _________
3.  In unorganized sector the employment terms are not _________
4. In recent times there has been a growth in _________
5. Mahatma Gandhi National Rural Employment Guarantee Act was passed in the year _________

Answers:

1. Employees
2. Very small
3. Fixed and Regular
4. Part-time employment
5. 2005

II. Match the following

1. Unorganised Sector – (i) Job security
2. Organised Sector – (ii) Iruvelpattu
3. Recent years – (iii) No fixed terms
4. Slater village – (iv) Increasing self-employment

Answer:

1. – iii
2. – i
3. – iv
4. – ii

IV. Write short answers

Question 1.
What is the basic need in the present world?
Answer:

1. The basic needs of every human being are food, clothes, and shelter
2. In the present world, one more thing also needs to be added to this list, is employment
3. To survive in the world, we all need employment to earn money.

Question 2.
Define the terms employer and employee.
Answer:

1. Those who are engaged in economic activities, in whatever capacity, are called employees.
2. People who employ these workers and pay rewards for their work in termed as employers.

Question 3.
In recent years what are the types of more flexible working patterns seen among the employees?
Answer:

1. In recent years, there has been a change in employment patterns.
2. This has helped the employer to develop more flexible working patterns among their employees.
3. The trends are
   • increasing self-employment
   • firms using fewer full-time employees and tending to offer more short term contracts
4. There has been a growth in part-time employment.
5. This may be due to the lifestyle of the people.

Question 4.
Mention the importance of the Mahatma Gandhi National Rural Employment Guarantee Act.
Answer:

1. Mahatma Gandhi National Rural Employment Guarantee of 2005 is able to provide work in rural areas for 100 days of employment in a year.
2. It aims to enhance livelihood security in rural areas.

V. Answer in a detail

Question 1.
Write a note on the case study of Employment in Iruvelpattu.
Answer:

1. Iruvelpattu is a village in Villupuram District, Tamil Nadu.
2. This village has been studied for more than 100 years by many scholars.
3. This village is also called Slater village as Gilbert Slater was the first scholar working in the University of Madras went with his students to study this village in 1916.
4. Over the years, many scholars surveyed the occupations of villagers and collected many more details of each person in the village.
5. The government brought social security awareness among the people of the village through their primary health care, provision of schools, maintenance of public distribution system.
6. Though this village underwent many changes, is still depended on agriculture as the main occupation
7. In the following chart we can notice that during 1981, out of 100 families, 24 were engaged in non-agriculture employment.
8. In 2008, the percentage of families engaged in such employment increased to 41.

Employment details of Households in Iruvelpattu (in %)

Occupation	% of Households
	1981	2008
Cultivators	42	33
Agricultural labourers	34	26
Non-agricultural labourers	24	41
All households	100	100

VI. HOTS

Question 1.
Suggest your views to increase agricultural productivity
Answer:

1. To facilitate the farmers to produce new farm inputs and enable them to sell their product in markets, villages should be linked with man dies.
2. Canals, Tube wells should be constructed to provide better irrigation facilities for the security of crops.
3. Adequate credit facilities should be made available at reasonable cheap rates in rural areas.
4. Marketing infrastructure should be widened and strengthened to help farmers to sell their products at better prices.
5. Efforts should be made towards completing the consolidation work with a specific period of time
6. Guidelines and advise could be given to the farmers regarding the adoption of new technology.
7. A proper climate should be generated to encourage the farm people to start employment in the subsidiary occupations. It will help to reduce the population pressure on land.
8. The farmers should be made familiar with the advantage of chemical fertilizer through exhibitions and these inputs should be made easily available through co-operative societies and panchayats.
9. To check up the subdivision and fragmentation of holding, the movement of co-operative farming should be launched.
10. In rural areas, more emphasis should be made to set up cottage and small scale industries.

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf Economics Chapter 1 Understanding Development: Perspectives, Measurement and Sustainability Text Book Back Questions and Answers, Important Questions Notes.

Tamilnadu Samacheer Kalvi 9th Social Science Solutions Economics Chapter 1 Understanding Development: Perspectives, Measurement and Sustainability

Samacheer Kalvi 9th Social Science Understanding Development: Perspectives, Measurement and Sustainability Text Book Back Questions and Answers

I. Choose the correct answer

Question 1.
Assertion (A): Development increases the quality of life.
Reason (R): People will have higher incomes, better education, better health and nutrition, less poverty.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true and (R) does not explain (A)
(c) (A) is correct and (R) is false
(d) (A) is false and (R) is true
Answer:
(a) Both (A) and (R) are true and (R) explains (A)

Question 2.
The term ‘Human resources’ refers to ___________
(a) investment on poor people
(b) expenditure on agriculture
(c) investment on assets
(d) collective abilities of people
Answer:
(d) collective abilities of people

Question 3.
For comparing development between countries, their is considered to be one of the most important attributes.
(a) growth
(b) income
(c) expenditure
(d) savings
Answer:
(b) income

Question 4.
___________ is considered a true measure of national income.
(a) GNP
(b) GDP
(c) NNP
(d) NDP
Answer:
(c) NNP

Question 5.
The income is also called per capita income. ___________
(a) average
(b) total
(c) people
(d) monthly
Answer:
(a) average

Question 6.
Which one of the following country is not a G-8 country?
(a) Japan
(b) Canada
(c) Russia
(d) India
Answer:
(d) India

Question 7.
Which one of the following country is not a member of SAARC?
(a) India
(b) Pakistan
(c) China
(d) Bhutan
Answer:
(c) China

Question 8.
Assertion (A): The Net National Product (NNP) is considered as a true measure of national output.
Reason (R): It is also known as national income.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true and (R) does not explain (A)
(c) (A) is correct and (R) is false
(d) (A) is false and (R) is true
Answer:
(a) Both (A) and (R) are true and (R) explains (A)

Question 9.
Assertion (A): Human resource is necessary for the progress of any country.
Reason (R): Investment in education and health of people can result in a high rate of returns in the future for a country.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true and (R) does not explain (A)
(c) (A) is correct and (R) is false
(d) (A) is false and (R) is true
Answer:
(a) Both (A) and (R) are true and (R) explains (A)

Question 10.
The Human Development Index (HDI) does not take into account the following dimension in its calculation
(a) Gender
(b) Health
(c) Education
(d) Income
Answer:
(a) Gender

Question 11.
Among the following states which state have the literacy rate (2011) higher than national average
(a) Andhra Pradesh
(b) Uttar Pradesh
(c) Tamil Nadu
(d) None of these
Answer:
(c) Tamil Nadu

Question 12.
Sex-ratio means
(a) the ratio between adult-male and adult female in a population
(b) the ratio between female and male in a population
(c) the relationship between male of female
(d) the number of females per thousand males
Answer:
(d) the number of females per thousand males

Question 13.
Inter-generational equality is ensured under the process of
(a) Industrial Progress
(b) Economic development
(c) Sustainable development
(d) Economic growth
Answer:
(c) Sustainable development

Question 14.
Find the odd one
(a) Solar energy
(b) Wind energy
(c) Paper
(d) Natural gas
Answer:
(c) Paper

Question 15.
________ is the state with highest installed solar capacity in India.
(a) Tamil Nadu
(b) West Bengal
(c) Kerala
(d) Andhra Pradesh
Answer:
(a) Tamil Nadu

Question 16.
________ resources are those which will get exhausted after years of use.
(a) Natural
(b) Renewable
(c) Non-Renewable
(d) New
Answer:
(c) Non-Renewable

II. Fill in the blanks

1. Economic progress of any country is known as __________
2. The head quarters of HRD Ministry is in __________
3. The state having the highest literacy rate in India is __________
4. Human Development Report of the world prepared and released by __________
5. Groundwater is an example of resource __________
6. The book An Uncertain Glory was written by __________

Answer:

1. Economic Development
2. Shastri Bhavan, New Delhi
3. Kerala
4. UNDP (United Nation Development Programme)
5. Renewable
6. Prof. Amartya Sen

III. Match the following

1. Development – (i) Wild life Protection Act
2. Human resource – (ii) Renewable resources
3. Solar energy – (iii) Part of daily life
4. 1972 – (iv) Education

Answer:

1. – (iii)
2. – (iv)
3. – (ii)
4. – (i)

IV. Give Short answers

Question 1.
What do you mean by development?
Answer:

1. The word ‘development’ refers to the progress of a particular field (or) a particular person.
2. Similarly, the economic progress of a country is known as ‘economic development’.
3. However, the interpretation of the concept development keeps On changing from time to time, from person to person.

Question 2.
What are the indicators of development?
Answer:

Question 3.
Why NNP is not considered as a useful measure to compare a country’s development with other countries?
Answer:

1. For measuring a country’s development, its income is considered to be one of the most important factors.
2. NNP is considered a true measure of National output.
3. So NNP is not considered a useful measure to compare a country’s development with other countries.

Question 4.
Why human resources is considered the foremost resource of any country?
Answer:

1. Human resource is necessary for the progress of any country.
2. Human resource refers to people who have the manpower which can be utilized in the production sector.
3. Therefore investment in human resource (education and health) can give a high rate of returns in the future.
4. Now the economists have realised that investment in human capital is as important as investment in physical capital.

Question 5.
Expand the following:

1. PPP
2. HDI

Answer:

1. PPP – Purchasing Power Parity.
2. HDI – Human Development Index.

Question 6.
Expand the following:

1. NNP
2. PCI

Answer:

1. NNP – Net National Product.
2. PCI – Per Capita Income.

Question 7.
What is ‘Solar Power’?
Answer:
Solar power is the conversion of energy from sunlight into electricity either directly using photovoltaic cells (or) indirectly using concentrated solar power.

V. Answer in detail

Question 1.
Discuss the policies for sustainable development.
Answer:

1. India depends on thermal and hydropower plants to meet its power needs. Both these sources have an adverse environmental impact.
2. Thermal power plants emit large quantities of carbon dioxide, which pollute the environment.
3. Solar power is the conversion of energy from sunlight into electricity either directly
   using photovoltaic cells or indirectly using concentrated solar power.
4. Solar panels absorb sunlight as a source of energy to generate electricity. A solar electric system can reliably produce electricity for our homes and offices.
5. These distributed solar systems are often installed by home and business owners to reduce their electricity costs. Solar power in India is a fast-developing industry.
6. Tamil Nadu is the state with the highest installed solar capacity in India.
7. Tamil Nadu is one of the leading solar power producing states in India. As of 31 July 2017, the total installed capacity in Tamil Nadu is 1,697 MW.

Question 2.
Describe in detail environmental policies in India. Ans:
Answer:

1. Environmental policies in India have been evolved considerably over the past three decades.
2. These policies have covered a wide range of issues such as air, water pollution, waste management, and biodiversity conservation.
3. India faces challenges in economic development, which has to be achieved with limited resources, minimum externalities, and in the presence of an uncertain climate.
4. One of the approaches to overcome this challenge is through the path of sustainable development.
5. The Supreme Court of India has interpreted and introduced new changes in environmental protection through a series of directions and judgments.

Question 3.
Differentiate between renewable and non-renewable resources.
Answer:
Renewable Resource:

1. These resources cannot be exhausted.
2. It can be used again and again.
3. Eg: Solar Energy, wind energy, tidal energy and hydroelectric, etc.,
4. It has low carbon emission and hence environment friendly.
5. The cost is low.
6. These resources are pollution-free.
7. The life of resource is infinite.

Non-Renewable Resource:

1. These resources can be exhausted one day.
2. Cannot be used repeatedly.
3. Eg: Coal, Petroleum, Natural gas, etc.,
4. It has a high carbon emission and damages the environment.
5. The cost is high.
6. Non-renewable resources pollute the environment.
7. The life of resources is finite and vanishes one day.

Question 4.
Mention any five environmental acts and their action. Ans:
Answer:
Act:

1. National Green Tribunal Act, 2010
2. Biological Diversity Act, 2002
3. The Environment (Protection) Act, 1986
4. Forest (Conservation) Act, 1980
5. Water (Prevention and control of pollution) Act, 1974
6. Wildlife Protection Act, 1972

Action:

1. Environmental protection and conservation of forests and other natural resources.
2. To provide for the conservation of biological diversity.
3. Providing for the protection and improvement of the environment.
4. Check deforestation and encourage afforestation of non-forest areas.
5. Provides maintenance and restoration and quality of all types of surface and groundwater.
6. Providing protection to wild animals and birds.

VI. Projects and Activities

Question 1.
List the various ways in which the problems of garbage and emissions are being dealt with around the world.
Answer:

Plastic bags, broken glass, obsolete cell phone (or) used battery cells, they are all used products that require appropriate disposal to limit their harm to the environment.
The various ways in which the problem of garbage and emissions are being dealt with:

1. Collection
2. transportation
3. dumping
4. recycling (or) sewage treatment.

Various waste disposal problems:

1. Production of too much waste.
2. Most of the waste is toxic.
3. Landfills are a problem as well.
4. Regulations are based on vested interests.
5. Reliance on dying technologies to reduce and recycle waste.
6. Some of the technologies marked as ‘green’ are not true in an actual sense.

You can do this project with the help of your teacher.

VII. HOTS

Question 1.
Write in detail what kind of environmental problems you face in your locality
Answer:
We face the following environmental problems in our locality:

1. Pollution of the air, water, soil, and others by chemicals.
2. Flood, an increased number of low-pressure depressions, cyclones, etc. from October to December.
3. The gradual caving in or sinking of areas near coastal land.
4. Usage and dumping of radioactive materials from hospital wastes.
5. Burning of garbage waste in open areas.
6. Increase of UV rays due to depletion of the Ozone Layer.
7. Insufficient energy, water, food, and other resources.
8. Other pollutions (noise, vibration, smell, radio wave damage, light pollution).
9. The extensive killing of animals and destroying of plants.
10. Rapid Global Warming.

VIII. Life Skill

Question 1.
How is the Per Capita income calculated?
Answer:
The average income is calculated by dividing the country’s total income by its total population. The average income is also called per capita income. Calculations on the per capita income of all countries are calculated only in the US dollar in order to compare the International level.

Samacheer Kalvi 9th Social Science Understanding Development: Perspectives, Measurement and Sustainability Additional Important Questions and Answers

I. Choose the best answer

Question 1.
India in said to be a _________ country.
(a) developed
(b) rich
(c) poor
(d) developing
Answer:
(d) developing

Question 2.
Development increases in the _________ of life.
(a) quantity
(b) quality
(c) nature
(d) style
Answer:
(b) quality

Question 3.
Which one of the following does not contribute to development?
(a) Stagnant
(b) Progress
(c) Improvement
(d) Bettering ourself
Answer:
(a) Stagnant

Question 4.
Assertion (A): The enrolment for higher education in Tamil Nadu is the highest in India.
Reason (R): Tamil Nadu’s literacy rate is higher than the national average.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true and (R) does not explain (A)
(c) (A) is correct and (R) is false
(d) (A) is false and (R) is true
Answer:
(b) Both (A) and (R) are true and (R) does not explain (A)

Question 5.
Assertion (A): Scientists, Economists, philosophers, and other social scientists are working together.
Reason (R) : Sustainable development means development should take place without damaging the environment and preserve it for the future.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true and (R) does not explain (A)
(c) (A) is correct and (R) is false
(d) (A) is false and (R) is true
Answer:
(b) Both (A) and (R) are true and (R) does not explain (A)

II. Fill in the blanks

1. Development refers to the __________ of a particular field or a particular person.
2.  __________ initiated bold social programmers such as midday meals in schools.
3. For the progress of any country __________ resource is necessary.
4. A rise in per capita income will always mean a rise in __________

Answer:

1. progress
2. Tamil Nadu
3. Human
4. aggregate real output

III. Match the following

1. Sustainable Development – (i) Progress
2. Human Resource – (ii) Per capita Income
3. Economic Development – (iii) Protect
4. Conserve – (iv) No damage to the Environment

Answer:

1. – iv
2. – i
3. – ii
4. – iii

IV. Give short answers

Question 1.
What is meant by the term economic development?
Answer:

1. The term economic development refers to the overall growth of all sectors of the economy by the adoption of new technologies.
2. The development improves the living standards of the people as well as the status of the country.

Question 2.
What is meant by the average Income?
Answer:

1. The average income is also called per capita income (PCI)
2. The average income is calculated by dividing a country’s total income by its total population.

Question 3.
We need to balance economic, social and environmental sustainability in equal harmony Why?
Answer:

1. Let us take the example of Ground water. It is an example of a renewable resource.
2. These resources are replenished by nature as in the case of crops and plants. If these resources are overused, more than what is being replenished by rain, then would raise the question – How sustainable development is possible?
3. Non-renewable resources are those which will get exhausted after years of use.
4. These resources cannot be replenished.
5. Therefore to achieve true sustainability we need to balance economic, social, and environmental sustainability in equal harmony.

Question 4.
Why is LPG subsidy being provided?
Answer:

1. In rural areas, people use wood, cow dung cake, or other bio mass as fuel.
2. This practice brings deforestation, wastage of cattle dung, and air pollution.
3. To rectify this situation, LPG subsidy is being provided, which is a clean fuel and reduce pollution to a large extent.

V. Answer in detail

Question 1.
Write a note on the indicators of economic development.
Answer:
(a) sentence:

1. The major indicators to measure the level of economic development are Net National
   Product (NNP), Per Capita Income (PCI), Purchasing Power Parity (PPP), Human Development Index (HDI).
2. Among these indicators, we shall discuss Per Capita Income and Net National Product.

(b) Per Capita Income:

1. For comparing a country’s development, there is considered to be one of the most important attributes.
2. Countries with higher income are more developed than with less income.
3. So income itself considered being one of the indicators of economic development.

(c) Net National Product:

1. Net National Product is considered as a true measure of national output.
2. It is also known as National Income.
3. A rise in per capita income will always mean a rise in aggregate real output. Hence this is better than that of National Income.
4. Since countries have different populations, comparing total income will not be suggestive of what an average person is likely to earn.
5. Hence we compare average income (Total income of the country divided by total population).
6. This average Income is also called Per Capita Income.

(d) Sentense:

1. According to the World Bank report, countries having more than 12,235 US dollars as Per Capita Income are called as rich countries.
2. India’s GDP per capita is 1,99,000 US dollars.
3. India is said to be a developing country.

VI. HOTS

Question 1.
What can a common man do to improve the economy of India?
Answer:
Some of the suggestions are given below:

1. Pay taxes.
2. Ask for bills whenever you purchase anything.
3. Do not buy gold and keep in lockers. Keep your money in circulation.
4. Use less electricity. Install solar panels.
5. Walk or use cycle whenever you can.
6. Do not indulge in corrupt practices.
7. Teach underprivileged children, the future citizens of India.
8. If possible start your own company, creating job opportunities.
9. Treat women properly by recognizing their efficiency.
10. Use your vote rightly and wisely.

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf Civics Chapter 6 Road Safety Text Book Back Questions and Answers, Important Questions, Notes.

Tamilnadu Samacheer Kalvi 9th Social Science Solutions Civics Chapter 6 Road Safety

Samacheer Kalvi 9th Social Science Road Safety Text Book Back Questions and Answers

I. Answer the following.

Question 1.
What are the benefits of wearing a helmet while driving?
Answer:
First of all, wearing a helmet helps to reduce traffic accidents. People will pay enough attention while they are driving their motors if they wear helmets. More over it helps us in protecting our eyes from the dust or terrible lights from other vehicles because we don’t need to use our hands or fingers to clean it while we are controlling our vehicles.

Question 2.
List out the factors of road accidents.
Answer:
Different factors to road accidents

1. Drivers
2. Pedestrians
3. Passengers
4. Vehicles
5. Road conditions
6. Weather conditions

Question 3.
Which colour in the signal means ‘stop?
Answer:
Red colour in the signal means ‘stop’

Question 4.
List out any three road safety rules:
Answer:

1. Know your signals
2. Stop, look and cross
3. Don’t run on roads

II. Answer in detail.

Question 1.
Explain the factors involved in road accidents.
Answer:
The different factors that contribute to road accident are,

1. Drivers: Over speeding, rash driving, violation of rules, failure to understand signs, fatigue, alcohol.
2. Pedestrians: Carelessness, illiteracy, crossing at wrong places, jaywalkers.
3. Passengers: Projecting their body parts outside vehicles, talking to drivers, alighting and boarding vehicles from the wrong side, traveling on foot boards, catching a running bus, etc.,
4. Vehicles : Failure of brakes or steering, tire burst, insufficient headlights, overloading.
5. Road Condition: Potholes, damaged roads, eroded roads merging of rural roads with highways, and illegal speed breakers.
6. Weather conditions: Fog, snow, heavy rainfall, wind storms, hail storms.

Question 2.
Explain in detail: The road safety rules.
Answer:
It is important for children to know about road safety rules and regulations. Here are a few basic

1. Know Your Signals
2. Stop, Look and Cross
3. Pay Attention – Listen
4. Don’t Run on Roads
5. Always Use Sidewalks
6. Never Stick Hands outside the Vehicle
7. Never cross Road at Bends
8. Don’t Rush.

Samacheer Kalvi 9th Social Science Road Safety Additional Important Questions and Answers

I. Answer in a word

1. This is required by law to drive _____________
2. A life saving _____________
3. They are ehere to key system safe _____________
4. A large vechicle to take precaution _____________ around
5. How the driver indicate which _____________ way they are turning
6. Something you should avoid while driving
7. Watch for there to even the road _____________
8. You apply this to stop your vechicle _____________
9. A pace by which you must abide by _____________
10. This indicates of how quickly you are travelling _____________
11. People, the driver is responsible for _____________
12. The part of your vehicle that meet the road _____________
13. An area where traffic fines double _____________
14. You should turn these on for safety _____________
15. A digital aid in navigating _____________

Answer:

1. licence
2. seat belt
3. Police
4. wide load
5. Blinker
6. Distractions
7. Pedestrian
8. Break
9. speed limit
10. speedo meter
11. Passengers
12. Tyre
13. work zone
14. Lights
15. GPS

II. Answer the following in brief.

Question 1.
Mention the direct consequences of accidents?
Answer:
The direct consequences of Accidents are:

1. Fatality (Death)
2. Injury
3. Damage to Property

Question 2.
What are the preventive measures for accidents?
Answer:
Preventive measures for accidents are,

1. Education and awareness about road safety.
2. Strict enforcement of law
3. Engineering:
   • Vehicle design
   • Road infrastructure.

Question 3.
Mention the major reasons for road accidents.
Answer:
The major reasons for road accident are

1. Negligence in driving
2. Drunk and drive
3. Overlooking the other vehicles
4. High speed
5. Improper driving training and
6. Non-stop long driving