Unit 6: Work Power and Energy — Online MCQ Test
PHYSICS · CLASS 11 INTERMEDIATE 1 YEAR · Telangana State Board
Practice Unit 6: Work Power and Energy with a free chapter-wise online MCQ test.
This chapter covers: This chapter covers work done by constant and variable forces work-energy theorem kinetic and potential energy conservative forces power and elastic inelastic collisions in one and....
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Unit 6: Work Power and Energy — Important Questions & Answers
Which of the following is the SI unit of work?
- A. Newton
- B. Joule
- C. Watt
- D. Pascal
Answer: B. Joule
Work is measured in joule (J). One joule is the work done when a force of 1 N produces a displacement of 1 m in the direction of the force.
Work is measured in joule (J). One joule is the work done when a force of 1 N produces a displacement of 1 m in the direction of the force.
Work done by a force is zero when the angle between force and displacement is:
- A. 0°
- B. 45°
- C. 90°
- D. 180°
Answer: C. 90°
Work done is given by W = Fs cos θ. When θ = 90°, cos 90° = 0, so the work done is zero.
Work done is given by W = Fs cos θ. When θ = 90°, cos 90° = 0, so the work done is zero.
A force of 10 N acts on a body and produces a displacement of 2 m in the same direction. The work done is:
- A. 5 J
- B. 10 J
- C. 20 J
- D. 30 J
Answer: C. 20 J
For force and displacement in the same direction, W = Fs = 10 × 2 = 20 J.
For force and displacement in the same direction, W = Fs = 10 × 2 = 20 J.
A 2 kg body moves with velocity 3 m/s. Its kinetic energy is equal to the potential energy of a body of mass 1 kg at height h. Taking g = 10 m/s^2, h is:
- A. 0.9 m
- B. 1.5 m
- C. 3.0 m
- D. 9.0 m
Answer: A. 0.9 m
Kinetic energy = 1/2 × 2 × 3^2 = 9 J. Setting mgh = 9 gives 1 × 10 × h = 9, so h = 0.9 m.
Kinetic energy = 1/2 × 2 × 3^2 = 9 J. Setting mgh = 9 gives 1 × 10 × h = 9, so h = 0.9 m.
Which of the following is NOT true for work done by a constant force?
- A. It depends on the magnitude of the force
- B. It depends on the displacement
- C. It depends on the angle between force and displacement
- D. It is always independent of the path taken
Answer: D. It is always independent of the path taken
For a constant force, work done depends on force, displacement, and angle. The statement about being independent of path is not a general property stated in this form.
For a constant force, work done depends on force, displacement, and angle. The statement about being independent of path is not a general property stated in this form.