9th class Physics unit 9 MCQs
chapter 9 MCQs 9th Class physics
Transfer of Heat:
1. The way by which transfer of heat takes place are:
a. Three
b. One
c. Four
d. Two
2. In solids, heat is transferred by:
a. Convection
b. Radiation
c. Absorption
d. Conduction
3. Metals are good conductors of heat due to the:
a. Small size of their molecules
b. Free electrons
c. Rapid vibrations of their atom
d. Big size of their molecules
4. False ceiling is done to:
a. Cool the room
b. Lower the height o
c. Insulate the ceiling
d. Keep the roof clean
5. What happens to the thermal conductivity of a wall if its thickness is doubled?
a. becomes half
b. becomes double
c. becomes one fourth
d. remains the same
6. Unit of rate of thermal energy is:
a. Joule
b. Kelvin
c. Second per joule
d. Joule per second
7. The unit of rate of conduction of thermal energy is:
a. K
b. Js-1
c. JK-1
d. J
8. Thermal conductivity of silver is:
a. 400 Wm-1 k-1
b. 245 Wm-1 k-1
c. 430 Wm-1 K-1
d. 105 Wm-1 K-1
9. Thermal conductivity of rubber is ……… Wm-1 k-1
a. 0.2 Wm-1 K-1
b. 0.08 Wm-1 K-1
c. 0.59 Wm-1 K-1
d. 1.7 Wm-1 K-1
10. The thermal conductivity of a dry air is ……… Wm-1 K-1
a. 0.02 Wm-1 k-1
b. 0.08 Wm-1 K-1
c. 0.026 Wm-1 K-1
d. 0 03 Wm-1 K-1
11. Thermal conductivity of brick is:
a. 0.8 Wm-1 K-1
b. 0.6 Wm-1 K-1
c. 1.7 Wm-1 K-1
d. 0.2 Wm-1 K-1
12. The unit of thermal conductivity is:
a. WmK-1
b. WmK
c. Wm2K-1
d. Wm-1K-1
13. The thermal conductivity of water is:
a. 0.8 Wm-1K-1
b. 245 Wm-1K-1
c. 0.59 Wm-1K-1
d. 0.6 Wm-1K-1
14. Thermal conductivity of ice is:
a. 1.7 Wm-1K-1
b. 1.7 Wm-1K-1
c. 2 Wm-1K-1
d. 0.9 Wm-1K-1
15. Which of the following is a bad conductor?
a. Iron
b. Gold
c. Wood
d. None of these
16. Example of a bad conductor is:
a. Wool
b. Gold
c. Graphite
d. Iron
17. In gases, heat is mostly transferred by:
a. Convection
b. Conduction
c. Absorption
d. Molecular collision
18. Convection is the process of transfer of heat due to the:
a. Upward movement of molecules
b. Random motion of molecules
c. Free movement of molecules
d. Downward movement of molecules
19. Rooms are heated using gas heaters by:
a. Radiation only
b. Conduction only
c. Convection only
d. Convection and radiation
20. Heat transfers through fluids by the method called:
a. Convection
b. Radiation
c. Absorption
d. Conduction
21. Reason of glider to remain in air is:
a. Radiation
b. Power
c. Convection
d. Conduction
22. Land breeze and sea breeze are the result of:
a. Radiation
b. Conduction
c. Absorption
d. Convection
23. In liquids, heat is mainly transferred by:
a. Radiation
b. Free electron
c. Convection
d. Conduction
24. Which of the following is a good radiator of heat?
a. A white surface
b. A shining silvered surface
c. A green colored surface
d. A dull black surface
25. The major source of energy is:
a. Nuclear fuels
b. Moon
c. Sun
d. Earth
26. A Leslie’s cube has faces:
a. Six
b. Two
c. Eight
d. Four
27. Which colour is a good absorber?
a. Shiny
b. White
c. Colored
d. Black
28. Warm clothes for winter season are:
a. Plastic
b. Woolen
c. Cotton
d. Silky
29. A good absorber of heat:
a. White surface
b. Dull black surface
c. Shining silvered surface
d. Colored surface
30. Global warming is due to a gas:
a. Carbon monoxide
b. Oxygen
c. Chlorine
d. Carbon dioxide
Click here to go directly on chapter no.1