# MCQ Questions for Class 9 Science Chapter 11 Work and Energy

MCQ Questions for Class 9 Science Chapter 11 Work and Energy will help them to focus on the most important topics and to better understand the material. It help you in active learning and also improve your problem-solving ability.

By taking the time to answer Chapter 11 Class 9 Science CBSE MCQ Questions with answers, you will be setting yourself up for success. These questions can provide a quick way to check understanding and identify any areas that may need more revision.

## Chapter 11 Work and Energy Class 9 Science MCQ Questions

1. The work done on an object does not depend upon the
(a) displacement
(b) force applied
(c) angle between force and displacement
(d) initial velocity of the object
▶ (d) initial velocity of the object

2. When a force retards the motion of a body, the work done is
(a) positive
(b) zero
(c) negative
(d) undefined
▶ (c) negative

3. Which of the following statements is correct regarding the relation between centripetal force and radius of the circular path?
(a) The work done by the centripetal force increases if the radius of the path is increased
(b) The work done by the centripetal force decreases by decreasing the radius
(c) The work done by the centripetal force increases by decreasing the radius
(d) The work done is always zero.
▶ (d) The work done is always zero.

4. A body falling from a height of 10m rebounds from a hard floor. It loses 20% of energy in the impact. What is the height to which it would rise after the impact?
(a) 7m
(b) 5m
(c) 8m
(d) 6m
▶ (c) 8m

5. Water stored in a dam possesses
(a) no energy
(b) electrical energy
(c) kinetic energy
(d) potential energy
▶ (d) potential energy

6. In an electric flashlight the chemical energy of the cell is
(a) converted into heat energy only
(b) converted into light energy only
(c) converted first into light and then heat energy
(d) converted first into heat and then light energy
▶ (d) converted first into heat and then light energy

7. A man carrying a bucket of water and walking on a rough level road with a uniform velocity does no work while carrying the bucket. Which of the following statements gives the correct reason for this?
(a) The displacement of the bucket is zero.
(b) There is no force acting on the bucket.
(c) The displacement of the bucket is in the direction of force applied.
(d) There is no displacement in the direction of the force applied.
▶ (d) There is no displacement in the direction of the force applied.

8. Work done by friction
(a) increases kinetic energy of body
(b) decreases kinetic energy of body
(c) increases potential energy of body
(d) decreases potential energy of body
▶ (b) decreases kinetic energy of body

9. Which of the following is not an example of potential energy?
(a) Water stored in a dam.
(b) A stretched bow and arrow system.
(c) A dog chasing a hare.
(d) A stone lying on the top of a roof.
▶ (c) A dog chasing a hare.

10. When a coil spring is compressed, the work is done on the spring. The elastic potential energy
(a) increases
(b) decreases
(c) disappears
(d) remains unchanged
▶ (a) increases

11. If force and displacement of the particle (in direction of force) are doubled, work should be
(a) doubled
(b) 4 times
(c) halved
(d) 1/4 times
▶ (b) 4 times

12. In which of the following cases is the potential energy of a spring minimum?
(a) When it is compressed
(b) When it is extended
(c) When it is at its natural length
(d) When it is at its natural length but is kept at a height h above the ground.
▶ (c) When it is at its natural length

13. One joule work is said to be done when
(a) a force of 1 N displaces a body by 1 cm
(b) a force of 1 N displaces a body by 1 m
(c) a force of 1 dyne displaces a body by 1 m
(d) a force of 1 dyne displaces a body by 1 cm
▶ (b) a force of 1 N displaces a body by 1 m

14. A body rolls down on inclined plane, it has
(a) only kinetic energy
(b) only potential energy
(c) both kinetic energy and potential energy
(d) neither kinetic energy nor potential energy
▶ (c) both kinetic energy and potential energy

15. Potential energy of a person is maximum when
(a) person is sitting on a chair
(b) person is standing
(c) person is lying on the ground
(d) person is sitting on the ground
▶ (b) person is standing

16. Mechanical energy of a body includes
(a) kinetic energy only
(b) potential energy only
(c) kinetic energy and potential energy
(d) none of these
▶ (c) kinetic energy and potential energy

17. Kinetic energy of a body depends
(a) on its mass only
(b) on its velocity only
(c) on its mass as well as on its velocity
(d) neither on its mass nor on its velocity
▶ (c) on its mass as well as on its velocity

18. Which one of the following is not the measure of energy?
(a) kWh
(b) erg
(c) Ws
(d) Js
▶ (d) Js

19. A rocket rises up vertically. What happens to its potential energy?
(a) It increases.
(b) It initially increases then decreases.
(c) It initially decreases then increases.
(d) It increases, till it becomes maximum.
▶ (d) It increases, till it becomes maximum.

20. Two boys A and B lift 100 bricks through the same height in 5 minutes and 6 minutes respectively. Then
(a) A has more power than B
(b) B has more power than A
(c) both have same power
(d) data insufficient
▶ (a) A has more power than B

21. Potential energy of a body depends on its
(a) position
(b) configuration
(c) position and configuration
(d) mass and velocity
▶ (c) position and configuration

22. Commercial unit of energy is
(a) joule
(b) kWh
(c) watt
(d) newton
▶ (b) kWh

23. If a body is raised through height h on the surface of earth and the energy spent is E , then for the same amount of energy the body on the surface of moon will rise through the height of
(a) 2h
(b) 6h
(c) 4h
(d) 12h
▶ (b) 6h

24. When the speed of a particle is doubled, the ratio of its kinetic energy to its momentum
(a) remains the same
(b) gets doubled
(c) becomes half
(d) becomes four times
▶ (b) gets doubled