Description: Practice Class 11 Physics Chapter 5 Work and Energy MCQs according to the FBISE HSSC-I syllabus. These exam-oriented questions cover work, energy, kinetic energy, gravitational potential energy, power, efficiency, conservation of energy, work-energy theorem, elastic potential energy, conservative and non-conservative forces, and renewable energy.
1. Work is done by a force when the force causes a:
A) change in mass B) displacement C) change in temperature D) change in colour
2. The SI unit of work is:
A) joule B) watt C) newton D) pascal
3. Work done by a constant force is given by:
A) W = F/d B) W = F + d C) W = Fd cos θ D) W = d/F
4. If force and displacement are in the same direction, work done is:
A) zero B) negative C) minimum D) maximum
5. When force is perpendicular to displacement, the work done is:
A) zero B) positive C) negative D) infinite
6. Work done by a force opposite to displacement is:
A) zero B) positive C) negative D) constant
7. A person carrying a bag horizontally at constant height does no mechanical work on the bag because the applied upward force is:
A) parallel to displacement B) perpendicular to displacement C) opposite to displacement D) equal to displacement
8. The area under a force-displacement graph represents:
A) power B) momentum C) acceleration D) work
9. Energy is defined as the capacity to:
A) do work B) produce mass C) stop time D) reduce displacement
10. The SI unit of energy is:
A) newton B) watt C) joule D) kilogram
11. Kinetic energy is the energy possessed by a body due to its:
A) position B) motion C) temperature D) shape only
12. The formula for translational kinetic energy is:
A) K = mv B) K = m/v C) K = 2mv² D) K = 1/2 mv²
13. If the speed of a body is doubled, its kinetic energy becomes:
A) four times B) two times C) half D) unchanged
14. If the mass of a moving body is doubled at constant speed, its kinetic energy becomes:
A) half B) four times C) double D) unchanged
15. Gravitational potential energy near Earth's surface is:
A) mgh² B) mgh C) mg/h D) mh/g
16. Gravitational potential energy increases when an object is:
A) moved downward B) stopped C) made lighter only D) raised higher
17. The reference level for gravitational potential energy is:
A) arbitrary B) always sea level C) always ground level D) always Earth's centre
18. A body at rest at a height above the ground possesses:
A) only kinetic energy B) only thermal energy C) gravitational potential energy D) no energy
19. When an object falls freely without air resistance, its gravitational potential energy is mainly converted into:
A) chemical energy B) kinetic energy C) nuclear energy D) electrical energy
20. At the highest point of a vertically thrown object, its kinetic energy is:
A) maximum B) negative C) equal to total mass D) minimum
21. Mechanical energy is the sum of:
A) kinetic and potential energies B) mass and momentum C) force and power D) heat and temperature
22. In the absence of friction and air resistance, total mechanical energy is:
A) increasing B) decreasing C) constant D) zero
23. The law of conservation of energy states that energy can be:
A) created but not destroyed B) transformed from one form to another C) destroyed but not created D) created from nothing
24. A machine cannot produce more energy than the energy supplied to it because of:
A) Newton's first law B) law of inertia C) law of gravitation D) conservation of energy
25. Power is defined as the rate of doing:
A) work B) force C) momentum D) displacement
26. The SI unit of power is:
A) joule B) newton C) watt D) pascal
27. One watt is equal to:
A) one joule B) one joule per second C) one newton per second D) one kilogram metre
28. A machine does 600 J of work in 20 s. Its power is:
A) 12 W B) 20 W C) 300 W D) 30 W
29. If the same work is done in half the time, the power is:
A) doubled B) halved C) unchanged D) zero
30. Efficiency of a machine is the ratio of:
A) input work to output work B) input power to output power C) useful output energy to input energy D) loss to input energy
31. The efficiency of a real machine is always:
A) greater than 100% B) less than 100% C) exactly 100% D) zero
32. A machine has an input energy of 500 J and useful output energy of 400 J. Its efficiency is:
A) 20% B) 40% C) 80% D) 75%
33. Energy lost due to friction is commonly converted into:
A) thermal energy B) mass C) gravitational energy D) nuclear energy
34. A stretched spring stores:
A) kinetic energy only B) gravitational energy only C) elastic potential energy D) nuclear energy
35. The work done in stretching an ideal spring is stored as:
A) thermal energy B) elastic potential energy C) kinetic energy only D) chemical energy
36. For a spring obeying Hooke's law, elastic potential energy is:
A) kx B) 2kx C) kx² D) 1/2 kx²
37. If the extension of an ideal spring is doubled, its stored elastic potential energy becomes:
A) four times B) two times C) half D) unchanged
38. The work done by a conservative force around a closed path is:
A) maximum B) negative C) zero D) infinite
39. Gravitational force is an example of a:
A) non-conservative force B) conservative force C) contact force only D) frictional force
40. Friction is generally classified as a:
A) conservative force B) central force C) gravitational force D) non-conservative force
41. If the net work done on an object is positive, its kinetic energy:
A) decreases B) remains zero C) increases D) must become negative
42. The work-energy theorem states that net work done on an object equals the change in its:
A) potential energy B) kinetic energy C) mass D) power
43. If net work on a body is zero, its kinetic energy:
A) must increase B) must decrease C) must be negative D) does not change
44. A force of 10 N moves an object 5 m in the direction of the force. The work done is:
A) 50 J B) 2 J C) 15 J D) 0.5 J
45. A 2 kg object moves at 3 m/s. Its kinetic energy is:
A) 3 J B) 6 J C) 9 J D) 18 J
46. A 5 kg object is raised through 4 m. Taking g = 10 m/s², its gravitational potential energy gained is:
A) 20 J B) 200 J C) 50 J D) 400 J
47. A 1000 kg car moving at 10 m/s has kinetic energy:
A) 5,000 J B) 10,000 J C) 50,000 J D) 100,000 J
48. Renewable energy sources are those that:
A) are naturally replenished B) can never be used twice C) always produce zero energy D) contain no energy
49. Which is a renewable energy source?
A) coal B) natural gas C) solar energy D) petroleum
50. A perpetual motion machine of the first kind would violate the:
A) law of gravitation B) law of conservation of energy C) law of reflection D) principle of moments
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Syllabus & SLO Alignment
FBISE syllabus: National Curriculum of Pakistan 2022–23, FBISE Assessment Framework for Physics Grade XI.
Content area: Domain B – Mechanics
Relevant SLOs: P-11-B-27 to P-11-B-32
Alignment: Work from force–displacement graphs; elastic potential energy; kinetic energy; work–energy theorem; conservative and non-conservative forces; applications in resistive media.
Assessment note: The FBISE framework distinguishes summative SLOs used in the final examination from formative SLOs used in teaching-learning. MCQs on this page should be treated as practice aligned to the listed content/SLOs, not as a reproduction of the official FBISE paper.