32 MCQ Questions for Class 9 Science: Chapter 10 Work And Energy
Question 1. What is the scientific definition of work?
a) Exerting force without displacement
b) Mental or physical activity to achieve a purpose
c) Displacement of an object due to applied force
d) Exerting force along with displacement in the direction of the force
Answer:
d) Exerting force along with displacement in the direction of the force
Question 2. The unit of work in the International System of Units is:
a) Newton
b) Joule
c) Watt
d) Kilogram
Answer:
b) Joule
Question 3. Which of the following is an example of a situation where no work is done?
a) Lifting a book from the floor to the table
b) Pushing a wall with no movement
c) A car descending a hill
d) Pulling a cart on a level road
Answer:
b) Pushing a wall with no movement
Question 4. The energy possessed by a body due to its motion is called:
a) Potential energy
b) Kinetic energy
c) Thermal energy
d) Chemical energy
Answer:
b) Kinetic energy
Question 5. Kinetic energy of an object is given by the formula:
a) KE = 1/2 mv²
b) KE = mgh
c) KE = mv
d) KE = 1/2 mgh
Answer:
a) KE = 1/2 mv²
Question 6. Potential energy is the energy possessed by an object due to its:
a) Motion
b) Position or shape
c) Temperature
d) Chemical composition
Answer:
b) Position or shape
Question 7. The potential energy of an object at a height h is given by the formula:
a) PE = mgh
b) PE = 1/2 mv²
c) PE = mv
d) PE = mgh²
Answer:
a) PE = mgh
Question 8. The law of conservation of energy states that:
a) Energy can be created but not destroyed
b) Energy can be neither created nor destroyed, only transformed
c) Energy is always lost when work is done
d) Energy can be destroyed but not created
Answer:
b) Energy can be neither created nor destroyed, only transformed
Question 9. Power is defined as:
a) The rate of doing work
b) The rate of change of velocity
c) The force applied on an object
d) The displacement of an object
Answer:
a) The rate of doing work
Question 10. The SI unit of power is:
a) Joule
b) Newton
c) Watt
d) Pascal
Answer:
c) Watt
Question 11. When is the work done by a force considered to be negative?
a) When the force acts in the direction opposite to displacement
b) When the force acts in the same direction as displacement
c) When there is no displacement
d) When the force is not applied
Answer:
a) When the force acts in the direction opposite to displacement
Question 12. What happens to the potential energy of a freely falling object?
a) It increases
b) It decreases
c) It remains constant
d) It first increases then decreases
Answer:
b) It decreases
Question 13. What is the potential energy of an object at a height dependent on?
a) The mass of the object and the height from the ground
b) The speed of the object
c) The temperature of the environment
d) The time for which the object is at the height
Answer:
a) The mass of the object and the height from the ground
Question 14. The law of conservation of energy states that:
a) Energy can be created and destroyed
b) Energy cannot be converted from one form to another
c) Energy can be neither created nor destroyed, only transformed
d) Total energy of the universe is decreasing
Answer:
c) Energy can be neither created nor destroyed, only transformed
Question 15. What is the SI unit of power?
a) Newton
b) Joule
c) Watt
d) Pascal
Answer:
c) Watt
Question 16. Power is defined as:
a) The rate of change of velocity
b) The force applied on an object
c) The rate of doing work or the rate of transfer of energy
d) The displacement of an object
Answer:
c) The rate of doing work or the rate of transfer of energy
Question 17. A boy of mass 50 kg runs up a staircase of 45 steps in 9 s. If the height of each step is 15 cm, what is his power? (g = 10 m/s²)
a) 100 Watts
b) 250 Watts
c) 375 Watts
d) 500 Watts
Answer:
c) 375 Watts
Question 18. Kinetic energy is the energy possessed by an object due to its:
a) Position or shape
b) Motion
c) Temperature
d) Chemical composition
Answer:
b) Motion
Question 19. The potential energy of an object of mass m at a height h is given by the formula:
a) KE = 1/2 mv²
b) PE = mgh
c) PE = mv
d) PE = 1/2 mgh
Answer:
b) PE = mgh
Question 20. What is the kinetic energy of an object of mass m moving with a velocity of 5 m/s?
a) 25 J
b) 12.5 J
c) 10 J
d) 5 J
Answer:
b) 12.5 J
Question 21. The rate at which an object does work is measured in __________.
Fill in the blank.
Answer:
Watts
Question 22. The kinetic energy of an object is directly proportional to the square of its __________.
Fill in the blank.
Answer:
Velocity
Question 23. An object at a certain height has __________ energy due to its position.
Fill in the blank.
Answer:
Potential
Question 24. The energy possessed by a wound-up spring is an example of __________ energy.
Fill in the blank.
Answer:
Elastic potential
Question 25. __________ is the ability to do work.
Fill in the blank.
Answer:
Energy
Question 26. When work is done by a force, the energy of the object on which it is done __________.
Fill in the blank.
Answer:
Changes
Question 27. Energy can be created and destroyed. (True/False)
Answer:
False
Question 28. Work is said to be done only when an object moves through some distance as a result of a force. (True/False)
Answer:
True
Question 29. Potential energy is dependent on the mass and the height of the object above the ground. (True/False)
True / False
Answer:
True
Question 30. The work done on an object is always positive. (True/False)
Answer:
False
Question 31. The potential energy of a ball increases when it is thrown upwards. (True/False)
Answer:
True
Question 32. Friction always does negative work. (True/False)
Answer:
False
Question on Match the Columns
Unmatched Columns – Questions
| Column A | Column B |
|---|---|
| (i) Work | (a) Energy of position or shape |
| (ii) Kinetic Energy | (b) Rate of doing work or transferring energy |
| (iii) Potential Energy | (c) Energy due to motion |
| (iv) Law of Conservation of Energy | (d) Force times displacement in the direction of force |
| (v) Power | (e) Energy cannot be created or destroyed, only transformed |
Matched Columns – Answer
| Column A | Column B |
|---|---|
| (i) Work | (d) Force times displacement in the direction of force |
| (ii) Kinetic Energy | (c) Energy due to motion |
| (iii) Potential Energy | (a) Energy of position or shape |
| (iv) Law of Conservation of Energy | (e) Energy cannot be created or destroyed, only transformed |
| (v) Power | (b) Rate of doing work or transferring energy |
