# Physics Question Answer Practice Set-4

1. The musical Instrument is a device for converting -
Ans: Mechanical energy into Sound energy

2. Candle converts -
Ans: Chemical energy into Light energy and Thermal energy

3. The electric cell (Battery) is a device for converting -
Ans: Chemical energy into Electrical energy

4. Coal converts -
Ans: Chemical energy into Thermal energy

5. Heat Engine converts -
Ans: Heat energy into Mechanical energy

6. The electric bulb is a device for converting -
Ans: Electrical energy into Light energy

7. In which processes light energy is converted into chemical energy -
Ans: Photosynthesis

8. Rate of doing work by a body is called -
Ans: Power

9. What is the SI unit of Power -
Ans: Watt or Joule

10. One Watt equal to -
Ans: 1 J/s

11. One Horse Power equal to -
Ans: 746 watt (In British system)

12. One Horse Power equal to -
Ans: 735.5 watt (In Matric system)

13. One watt second equal to -
Ans: 1 joule

14. One watt hour equal to -
Ans: 3600 joule

15. What is represented by the area under power-time graph-
Ans: Work

16. The universal law of gravitation was propounded by -
Ans: Newton

17. Universal attractive force is called -
Ans: Gravitation

18. Gravitation force always attractive in -
Ans: Nature

19. Which force weakest force but is a long range force -
Ans: Gravitation force

20. Who gave the first experimental value of G-
Ans: Cavendish

21. The value of g at the surface of the moon is -
Ans: 1/6th of that on the earth

22. If the weight of a man is 600 N on the earth, then his weight on the moon will be -
Ans: 100N

23. The value of g at the surface of the earth is
Ans: 9.8 m/s2

24. The value of g at the center of the earth is -
An: Zero

25. When we go above the surface of the earth, the acceleration due to gravity goes on -
Ans: Decreases