Lesson 5 – Work, Energy and Power Very Short Questions & Answers (1 Mark)


Q1. What is work?

Work is said to be done when a force acting on a body produces displacement in the direction of the force.


Q2. Write the SI unit of work.

The SI unit of work is joule (J).


Q3. Write the SI unit of energy.

The SI unit of energy is joule (J).


Q4. What is zero work?

When force acts on a body but produces no displacement in the direction of force, the work done is zero.


Q5. Give one example of zero work.

Work done by centripetal force in circular motion is zero.


Q6. Define energy.

Energy is the capacity of a body to do work.


Q7. What is kinetic energy?

Kinetic energy is the energy possessed by a body due to its motion.


Q8. Write the formula for kinetic energy.

Kinetic energy = ½ mv²


Q9. What is potential energy?

Potential energy is the energy possessed by a body due to its position or configuration.


Q10. What is power?

Power is the rate of doing work.


Q11. Write the formula for power.

Power = Work / Time


Q12. Write the SI unit of power.

The SI unit of power is watt (W).


Q13. What is positive work?

Work is positive when force and displacement are in the same direction.


Q14. What is negative work?

Work is negative when force and displacement are in opposite directions.


Q15. Write one example of negative work.

Work done by friction on a moving body is negative.


Q16. What is instantaneous power?

Instantaneous power is the power at a particular instant and is given by P = F · v


Q17. What does the work–energy theorem state?

The work done by the net force acting on a body is equal to the change in its kinetic energy.


Q18. What happens to kinetic energy when velocity is doubled?

Kinetic energy becomes four times.


Q19. What happens to kinetic energy when mass is doubled?

Kinetic energy becomes double.


Q20. Write the dimensional formula of power.

[M L² T⁻³]


1-Mark Exam Tip

  • Write answers in one line only.
  • Use exact textbook words.
  • No explanation required.

“One-mark questions test accuracy, not length.”

Work, Energy & Power – Complete Physics Library

This is the MASTER LIBRARY PAGE for the complete chapter Work, Energy and Power, prepared for Intermediate, IIT-JEE (Main & Advanced), NEET and competitive exams.

All concepts are explained from basic to IIT level, including theory, derivations, numerical problems, objective questions, previous year questions, tough IIT problems, tricks and cautions.

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