Class IX Chapter : Work and Energy Date of Taking Test : December 25, 2024 Time: 20 Minutes 1. An object is falling freely from a height x. Which of the following is the type of energy possessed by the object after it has fallen a height of x/2? (a) Only potential energy (b) Only kinetic energy (c) Half potential and half kinetic energy (d) Less potential and more kinetic energy None 2. A microphone converts ___________ into ___________ energy in public address system. (a) electrical, sound (b) microwave, sound (c) sound, mechanical (d) sound, electrical None 3. A car moving on a levelled road accelerates and acquires a velocity 4 times the initial velocity. During this process, the potential energy of the car _________. (a) does not change (b) becomes twice that of initial potential energy (c) becomes 4 times that of initial potential energy (d) becomes 16 times that of initial potential energy None 4. A car moving on a levelled road accelerates and acquires a velocity 2 times the initial velocity. During this process, the kinetic energy of the car __________ (a) does not change (b) becomes twice that of initial kinetic energy (c) becomes 4 times that of initial kinetic energy (d) becomes 16 times that of initial kinetic energy None 5. For a negative work, force makes an angle of ___________ with the displacement. (a) 0° (b) 45° (c) 90° (d) 180° None 6. A girl carrying a 3 kg mass on her back climbs up 10 steps, each of height 10 cm then the work done by her against gravitational energy is ___________ (a) 0 J (b) 0.6 J (c) 30 J (d) 6000 J None 7. Identify the situation where work is being done by the force. (a) The weight of a book at rest on a table. (b) The tension in an elastic band wrapped around a parcel (c) The pull of a moving railway engine on its coaches. (d) The push of a person’s feet when standing on the concrete floor. None 8. If a force F applied on a body gives it velocity v, its power will be (a) Fv (b) F/v (c) Fv2 (d) v2/F None 9. In the given diagram if force F = 2 N and displacement s = 3 m, then work done W will be _________. (a) 6 N m (b) 2 N m (c) 3 N m (d) 12 N m None 10. None 11. Which of the following energy conversion is involved in geyser? (a) Electric energy into mechanical energy (b) Mechanical energy to heat energy (c) Electric energy into heat energy (d) Mechanical energy to electrical energy None 12. A bullet that has been fired from a gun can pierce a target due to its __________ (a) Heat energy (b) Mechanical energy (c) Chemical energy (d) Kinetic energy None 13. If the velocity of the moving cart is reduced to 1/3rd of its virtual velocity, then the kinetic energy _________. (a) increases to 1/9th of its initial value (b) decreases to 1/9th of its initial value (c) increases to 1/3rd of its initial value (d) decreases to 1/3rd of its initial value None 14. Assertion (A): A boy trying to push the wall is not doing work Reason (R): Work is said to be done when the force acting on a body displaces the body. (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true and R is NOT the correct explanation of A (c) A is true but R is false (d) A is false but R is true None 15. Assertion (A): Work done by a constant force is equal to the product of force and the displacement of the object in the direction of force. Reason (R): Work is a vector quantity. (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true and R is NOT the correct explanation of A (c) A is true but R is false (d) A is false but R is true None 16. Assertion (A): Work done can never be zero. Reason (R): Work done by a constant force is equal to the product of force and the displacement of the object in the direction of force. (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true and R is NOT the correct explanation of A (c) A is true but R is false (d) A is false but R is true None 17. Assertion (A): The S.I unit of energy is also joule. Reason (R): The energy possessed by an object is a measure of its capacity to do work (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true and R is NOT the correct explanation of A (c) A is true but R is false (d) A is false but R is true None 18. Assertion (A): If 1J of work done is 1 s, then the power dissipated is 1 W Reason (R): Power is the rate at which work is done. (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true and R is NOT the correct explanation of A (c) A is true but R is false (d) A is false but R is true None 1 out of 1 Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Name * Email * Website Comment * Save my name, email, and website in this browser for the next time I comment.