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Work and energy MCQ question and answer for competition exam

 1) 1 kwH  is equal to how many joules:-

 A. 1000 joules

 B. 3.6 × 10⁵ joules

 C. 3.6×10⁶ joules

 D. 3.6×10³ joules

 Ans.C.  3.6 × 10⁶  joules


 2) The value of 1HP(horse power)  is equal to:-

 A. 500 watts

 B. 240 watts

 C. 340 watts

 D. 746 watts

 Ans.4.  746  Watts


 3) An object situated at a height of h m is stored in:-

 1. potential energy

 2. Kinetic Energy

 3. Gravitational Energy

 4.Magnetic Energy

 Ans.  1.  potential energy


 4) The SI  unit of power is :-

 1. Watt

 2. joule

 3. Tesla

 4. Ohms

 Ans.1.  Watt


 5) The SI  unit of work is :-

 1. Watts

 2. joule

 3.Tesla

 4. Ohms

 Ans.2.  joule


 6) When an object of mass m is raised to a height h , the potential energy stored in it will be:-

 1. ½mv²

 2. mh

 3. mgh

 4. mv

 Ans.3. mgh


 7) The formula of work is :-

 1. Force × Time

 2. Force × Mass

 3.Force ×  Displacement

 4.force ×  velocity

 Ans.  3. Force × Displacement


 8) An object of mass m  is raised to a height h , then the total work done in this case will be:-

 1.  mgh

 2. 3mgh

 3. gh

 4. mg

 Ans.1. mgh


 Note:- The work done in such situation is equal to the value of potential energy.


 9) Power is :-

 1. Ability to work

 2. Strength

 3. a form of energy

 4. Working Rate

 Ans.4.  working rate


 10. When an object is thrown vertically

 Energy will be :-

 A. lowest at highest point

 B. highest at the highest point

 C. Zero at the highest point

 D. same at all points

 Ans: D. Same at all points


 11. An object is thrown vertically up. The kinetic energy at the end point will be :-

 A. max

 B. Nil

 C. General

 D. does not remain fixed.

 Ans : B. Nil


 12. Throwing an object vertically upwards will increase with height :-

 A. Kinetic energy

 B. potential energy

 C. Acceleration

 D. Momentum

 Ans: B. Potential Energy


 13. The device that converts sound energy into electrical energy is :-

 A. Telephone

 B. Dynamo

 C. Microphone

 D. Radio

 Ans: C. Microphone


 14. The energy stored in the springy clock is :-

 A. Kinetic energy

 B. potential energy

 C. chemical energy

 D. nuclear power

 Ans : B. Potential Energy


 15. What is the SI unit of potential energy :-

 A. joule

 B. Newton

 C. joule-second

 D. joule/second

 Ans: A. Joule


 16. Which of the following represents kinetic energy :-

 A.  mgh

 B. 2mgh

 C. mgh

 D. ½mv²

 Ans: D. ½mv²


 17.  How many ergs are there in 1 Joule :-

 A.  10⁹ ergs

 B.  100 ergs

 C.  10⁷ ergs

 D.  10⁵ ergs

 Ans: C. 10⁷ ergs


 18. Which of the following is the unit of power :-

 A. joule meter

 B. Newton meter

 C. joule second

 D. joule/second

 Ans: D. Joule/second


 19. The ability to do work is called :-

 A. Work

 B. Energy

 C. power

 D.  force

 Ans: B. Energy


 20. If displacement is zero then :-

 A. Work will be more.

 B. Work will be less.

 C. Work will be zero.

 D. Work will be positive.

 Ans: C. Work will be zero.


 21. Which of the following represents work :-

 A.  Force × Displacement

 B.  Force / Displacement

 C.  Power × Displacement

 D.  power/time

 Ans: A. Force × Displacement


 22. If the direction of force is perpendicular to the direction of displacement (90°), then the work will be :-

 A. max

 B. Minimum

 C. zero

 D. negative

 Ans: C. Nil


 23. If the direction of force is in the direction of displacement, then the work will be :-

 A. positive

 B. negative

 C. zero

 D. none of these

 Ans: A. Positive


 24.  1 Newton  is equal to how many dyne :-

 A.  100 dyne

 B.  10⁷ dyne

 C.  10³ dyne

 D.  10⁵ dyne

 Ans: D. 10⁵ dyne


 25. Which of the following is true regarding work :-

 A. W = FS sinθ

 B.  W = FS tanθ

 C.  W = FS cosθ

 D.  W = FS cotθ

 Ans: C. W = FS cosθ


 26. If the angle (θ) between the force and the displacement is 0°, then the work will be :-

 A. Nil

 B. positive

 C. negative

 D. Minimum

 Ans: C. Negative

 27. If the angle (θ) between the force and the displacement is 180°, then work will be :-

 A. max

 B. Nil

 C. positive

 D. negative

 Ans: D. Negative


 28. The work done by the engine of the car in accelerating the car is :-

 A. negative

 B. positive

 C. zero

 D. none of these

 Ans: B. Positive


 29. The brake is applied to the moving car.  The work done by the brakes of the car is :-

 A. negative

 B. positive

 C. zero

 D. cannot be known.

 Ans: A. Negative


 30. The area covered by the graph in the force-displacement graph is :-

 A. Quantity of energy

 B. amount of force

 C. Quantity of power

 D. Quantity of work

 Ans: D. Quantity of work


 31. Which of the following is a unit of work :-

 A. Nm

 B. N/m

 C. Nm²

 D. Nm

 Ans: A. Nm


 32. 1 watt is equal to :-

 A. 1 joule-second

 B.  1 joule

 C. 1 (joule/second)

 D.  1 erg

 Ans: C. 1( Joule/second)


 33. How many joules are there in 1 electron volt :-

 A. 1.6 × 10 -¹²

 B. 1.6 × 10⁶

 C. 1.6 × 10-¹⁰

 D. 1.6 × 10-¹⁹

 Ans: D. 1.6 × 10-¹⁹

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