Unit 10: Transfer of Thermal Energy (Quiz 1)

1. Conduction is a transfer of thermal energy through the

• difference in densities

• vibration of particles

• movement of particles from one place to another

• radiation of waves

2. Metals are good conductors of heat because

• metals have high melting point

• metals are shiny

• metals have free electrons

• metals are reactive

3. Which of the following is the best conductor of thermal energy?

• aluminium

• brass

• copper

• steel

4. Conduction happens in

• solid

• liquid only

• solid and liquid only

• solid, liquid and gas

5. Convection is a transfer of thermal energy due to

• vibration of the particles

• expansion of fluid only

• movement of molecules due to a difference in densitites

• radiation of wave

6. Convection currents are formed due to the change in ................................ of the fluid.

• temperature

• state

• density

• vibrations

7. An air-conditioner is placed at a high point in a room. This is because...

• coldness always travel downwards

• hotness always travel upwards

• cooled air is less dense

• cooled air is denser

8. Convection happens in

• liquid only

• gas only

• liquid and gas only

• solid, liquid and gas

9. Radiation is a transfer of thermal energy by

• movement of free electrons

• movement of molecules due to a difference in densities

• wave which does not require a medium to travel through

• vibration of particles

10. The inner surface of a vacuum flask has silvered surfaces. This is because...

• The inner surface is a poor emitter of thermal energy.

• The inner surface is a good emitter of thermal energy.

• The inner surface is a poor absorber of thermal energy.

• The inner surface is a good absorber of thermal energy.