Lesson 5 – Work, Energy and Power Objective Questions (MCQs & Numericals)
This section covers objective-type questions frequently asked in Intermediate examinations. These questions test concept clarity and formula application.
A. Multiple Choice Questions (MCQs)
Q1. When is work said to be done on a body?
a) When force acts on the body
b) When displacement occurs
c) When force causes displacement in its direction
d) When body is at rest
Answer: (c)
Q2. The SI unit of work is:
a) Newton
b) Joule
c) Watt
d) Erg
Answer: (b)
Q3. Work done by centripetal force in circular motion is:
a) Positive
b) Negative
c) Zero
d) Maximum
Answer: (c)
Q4. A body moving with uniform velocity has:
a) Increasing kinetic energy
b) Decreasing kinetic energy
c) Constant kinetic energy
d) Zero kinetic energy
Answer: (c)
Q5. The kinetic energy of a body is doubled if:
a) Velocity is doubled
b) Velocity is halved
c) Mass is doubled
d) Mass is halved
Answer: (c)
Q6. The work–energy theorem states that work done is equal to:
a) Kinetic energy
b) Potential energy
c) Change in kinetic energy
d) Total energy
Answer: (c)
Q7. Power is defined as:
a) Work × time
b) Work / time
c) Force × displacement
d) Energy × velocity
Answer: (b)
Q8. The SI unit of power is:
a) Joule
b) Newton
c) Watt
d) Ampere
Answer: (c)
B. Numerical Objective Questions
Q9. Find the kinetic energy of a body of mass 1 kg moving with velocity 4 m/s.
K.E = ½ mv² = ½ × 1 × 16 = 8 J
Q10. A force of 20 N acts on a body producing displacement of 3 m. Find the work done.
W = Fs = 20 × 3 = 60 J
Q11. Calculate the power when 100 J of work is done in 5 seconds.
Power = Work / Time = 100 / 5 = 20 W
Q12. A body of mass 2 kg moves with velocity 5 m/s. Find its kinetic energy.
K.E = ½ mv² = ½ × 2 × 25 = 25 J
C. Assertion–Reason Type (Very Important)
Q13. Assertion: Work done by friction is negative.
Reason: Friction always opposes motion.
a) Both true and reason explains assertion
b) Both true but reason does not explain
c) Assertion true, reason false
d) Both false
Answer: (a)
Q14. Assertion: Power depends on time.
Reason: Power is rate of doing work.
Answer: (a)
Objective Exam Tips
- Remember units clearly.
- Check sign of work (+, −, 0).
- Velocity change affects kinetic energy.
- Read assertion–reason carefully.
“Objective questions reward clarity, not memory.”
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.
📚 Complete Lesson Index (Part 1 – Part 39)
- Part 1 – Introduction to Work
- Part 2 – Types of Work
- Part 3 – Variable Force & Graphs
- Part 4 – Kinetic Energy
- Part 5 – Work–Energy Theorem
- Part 6 – Potential Energy
- Part 7 – Conservative Forces
- Part 8 – Mechanical Energy
- Part 9 – Power
- Part 10 – Power Applications
- Part 11
- Part 12
- Part 13
- Part 14
- Part 15
- Part 16
- Part 17
- Part 18
- Part 19
- Part 20
- Part 21
- Part 22
- Part 23
- Part 24
- Part 25
- Part 26
- Part 27
- Part 28
- Part 29
- Part 30
- Part 31
- Part 32
- Part 33
- Part 34
- Part 35
- Part 36
- Part 37
- Part 38
- Part 39 – Final IIT Tough Problems & Solutions
Prepared by: Shaktimatha Learning 🌱
Strong Concepts • Smart Practice • Exam Success
No comments:
Post a Comment