Top MCQs on Work, Power, and Energy for Class 11 Physics | NEET & CBSE
Class 11 Physics Work, Power, and Energy Multiple Choice Questions
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Class 11 Physics Work, Power & Energy – Objective Questions
Q1. According to the Work-Energy Theorem, the work done by the net force on a particle is equal to the change in its:
a) Kinetic energy
b) Angular momentum
c) Linear momentum
d) Potential energy
Q2. A light and a heavy body have equal momentum. Which one has greater kinetic energy?
a) The lighter body
b) The heavier body
c) Both have equal K.E.
d) Data given is incomplete
Q3. Kinetic energy, with any reference, must be:
a) Positive
b) Zero
c) Negative
d) None of these
Q4. Work done by a conservative force is positive if:
a) Potential energy decreases
b) Kinetic energy increases
c) Kinetic energy decreases
d) Potential energy increases
Q5. The ...X... energy V(x) of the spring is said to be zero when the block–spring system is in the ...Y... position. Here X and Y refer to:
a) Potential, equilibrium
b) Kinetic, equilibrium
c) Mechanical, equilibrium
d) Vibrational, left
Q6. To determine the power output of an automobile, which of the following must be known?
a) Work performed and elapsed time
b) Force exerted and distance moved
c) Mass and amount of work performed
d) Final velocity and height
Q7. A vehicle is moving with a uniform velocity on a smooth horizontal road. The power delivered by its engine must be:
a) Increasing
b) Zero
c) Uniform
d) Decreasing
Q8. How much water can a 2 kW pump raise in one minute to a height of 10 m? (Take g = 10 m/s²)
a) 1200 kg
b) 100 kg
c) 2000 kg
d) 1000 kg
Q9. The engine of a vehicle delivers constant power. If the vehicle moves up an inclined plane, its velocity:
a) Must remain constant
b) Must increase
c) Must decrease
d) May increase, decrease, or remain same
Q10. A body projected vertically from Earth reaches a height equal to Earth’s radius before returning. The power exerted by gravity is greatest:
a) Just before hitting Earth
b) At the highest point
c) Constant throughout
d) Just after projection
Q11. When the force retards the motion of a body, the work done is:
a) Negative
b) Zero
c) Positive
d) None of these
Q12. A man pushes a wall and fails to displace it. He does:
a) No work at all
b) Positive but not maximum work
c) Negative work
d) Maximum positive work
Q13. A boy carrying a box on his head while walking on a level road is said to be doing no work. This statement is:
a) Correct
b) Incorrect
c) Partly correct
d) Cannot say
Q14. No work is done if:
a) All of these
b) Force and displacement are perpendicular
c) Force is zero
d) Displacement is zero
Q15. A particle is taken round a circle by a force. The work done by the force is:
a) Zero
b) Positive non-zero
c) Negative non-zero
d) None of these
Q16. Assertion (A): The work done in moving a body over a closed loop is zero for every force in nature.
Reason (R): Work done depends on the nature of force.
a) A correct, R correct; R not correct explanation of A
b) A correct, R incorrect
c) A incorrect, R correct
d) A correct, R correct; R is correct explanation of A
Q17. A motorcyclist skids and stops after covering 15 m. Stopping force = 100 N. The work done by the motorcycle on the road is:
a) Zero
b) 750 J
c) –1500 J
d) 1500 J
Q18. A ball moves on a frictionless inclined table without slipping. The work done by the table surface is:
a) Zero
b) Positive
c) Negative
d) None of these
Q19. A spring (k = 5 × 10³ N/m) is stretched 5 cm from natural length. The work required to stretch it a further 5 cm is:
a) 18.75 J
b) 25.00 J
c) 6.25 J
d) 12.50 J
Q20. A boy pushes a toy box 2.0 m along the floor with a force of 10 N directed downward at 60° to horizontal. The work done is:
a) 10 J
b) 12 J
c) 8 J
d) 6 J
Q21. A body of mass m moves in a circle of radius r with constant speed v. The work done by the centripetal force in half a revolution is:
a) mv²/r
b) Zero
c) mv²/2r
d) 2πr·mv
Q22. If the units of force and length are both increased four times, then the unit of energy increases by:
a) 16 times
b) 8 times
c) 2 times
d) 4 times
Q23. A man pushes a wall but it does not move. The work done is:
a) Negative
b) Positive but not maximum
c) No work at all
d) Maximum
Q24. A force of 5 N displaces a body through 10 m. If the work done is 25 J, the angle between force and displacement is:
a) 0°
b) 30°
c) 60°
d) 90°
Q25. Which of the following is a scalar?
a) Displacement
b) Electric field
c) Acceleration
d) Work
Q26. The work done against gravity in raising 10 kg mass to 1 m in 1 second is:
a) 49 J
b) 98 J
c) 196 J
d) 0 J
Q27. In an explosion, a body breaks into two unequal parts. Which is correct?
a) Both have equal momentum (magnitude)
b) Lighter has more momentum
c) Heavier has more momentum
d) Both have equal kinetic energy
Q28. A spring when stretched by distance S stores 10 J. Work required to stretch it another distance S is:
a) 30 J
b) 40 J
c) 10 J
d) 20 J
Q29. Which one is not a conservative force?
a) Gravitational force
b) Electrostatic force
c) Magnetic dipole force
d) Frictional force
Q30. Two masses m1 and m2 have equal kinetic energies. Ratio of their momenta is:
a) p1 : p2 = m1 : m2
b) m2 : m1
c) √m1 : √m2
d) m1² : m2²
Q31. Work done in lifting a box depends only on:
a) Speed of lifting
b) Strength of the man
c) Height raised
d) None
Q32. If the K.E. of a particle doubles, its momentum becomes:
a) Unchanged
b) Doubled
c) Quadrupled
d) Increased by √2
Q33. A stone thrown vertically upward has maximum potential energy:
a) During upward journey
b) At the highest point
c) During downward journey
d) At the bottom
Q34. If the speed of a motor car is tripled, the stopping distance increases by:
a) 3 times
b) 6 times
c) 9 times
d) More than 9
Q35. Potential energy decreases in which case?
a) Compressing a spring
b) Stretching a spring
c) Moving against gravity
d) Rising of an air bubble in water
Q36. In a perfectly elastic collision:
a) Only K.E. is conserved
b) Only momentum is conserved
c) Both momentum and K.E. are conserved
d) Neither is conserved
Q37. A motor develops 10 kW. Time taken to lift 200 kg mass through 40 m is:
a) 4 s
b) 5 s
c) 8 s
d) 10 s
Q38. An 80 kg man climbs 6 m high stairs in 10 s. Average horsepower is:
a) 0.63 HP
b) 1.26 HP
c) 1.8 HP
d) 2.1 HP
Q39. A ball moving at 10 m/s hits a wall and rebounds at 10 m/s. Which is true?
a) No acceleration
b) Only direction changed
c) Acceleration present due to momentum change
d) Momentum unchanged
Q40. A body falls from 10 m and rebounds losing 20% energy. Coefficient of restitution is:
a) 0.89
b) 0.56
c) 0.23
d) 0.18
Q41. In an inelastic collision:
a) Momentum is conserved, K.E. not conserved
b) Momentum not conserved, K.E. conserved
c) Both conserved
d) Neither conserved
Q42. For potential energy U = Ax²:
a) Force always pulls particle to origin if A > 0
b) Force pushes away for A > 0
c) Always repulsive
d) Independent of A
Q43. A motor pump is to deliver n times more water in same time. The power of motor must increase:
a) n times
b) n² times
c) n³ times
d) n⁴ times
Q44. If an object slightly displaced comes back to its original position, it is in:
a) Neutral equilibrium
b) Stable equilibrium
c) Unstable equilibrium
d) None
Q45. A body of mass m attached to spring constant k descends distance x. At equilibrium:
a) x = mg/k
b) x = 2mg/k
c) Zero acceleration at x/2
d) Upward acceleration = g
Q46. A particle of mass 0.1 kg moves along x-axis with potential U(x) = 5x – 4x². It has maximum speed at:
a) x = 0
b) x = 2 m
c) x = 4 m
d) Cannot oscillate
Q47. Work done by a spring is W = (1/2)kx². If spring compressed by distance x to natural length, then:
a) Work is positive
b) Work is negative
c) Both possible depending on direction
d) Zero
Q48. A particle dropped from height h with horizontal velocity. Its kinetic energy versus time graph is:
a) Linear increasing
b) Exponential
c) Constant
d) Decreasing
Q49. The potential energy of a particle under force F(x) = -kx + ax³ is:
a) U(x) = (1/2)kx² – (1/4)ax⁴
b) U(x) = -kx² + ax⁴
c) U(x) = kx³ + ax²
d) None
Q50. In elastic collision of two equal masses (one at rest), after collision:
a) Moving mass stops, other moves with same velocity
b) Both move with half velocity
c) Both move with equal velocities
d) Both remain at rest
Class 11 Physics Work, Energy and Power Question Bank with Answers
1.a 2.a 3.d 4.a 5.a 6.b 7.a 8.a 9.d 10.c
11.c 12.d 13.b 14.c 15.d 16.c 17.a 18.a 19.a 20.a
21.b 22.a 23.c 24.c 25.d 26.b 27.a 28.a 29.d 30.c
31.c 32.d 33.b 34.c 35.d 36.c 37.c 38.a 39.c 40.a
41.a 42.a 43.b 44.b 45.a 46.b 47.c 48.a 49.a 50.a
