Physics Quiz

Thermal Heat Transfer

Question 1

What is the method of heat transfer from the heater to the metal plate?

Answer: Radiation

Question 2

What is the method of heat transfer from the metal plate to the wax?

Answer: Conduction

Question 3

What is the method of heat transfer from the wax to the cork?

Answer: Conduction

Question 4

Which stopper will slide down first? Why?

Answer: Stopper from the dull black metal plate because black is a better absorber of heat than shiny surface.

Question 5

Which heat transfer method(s) will the vacuum layer of the thermal flask help to minimise?

Answer: Conduction and Convection

Question 6

Which heat transfer method(s) will the silvered wall of the thermal flask help to minimise?

Answer: Radiation

Question 7Which heat transfer method(s) will the plastic cap of the thermal flask help to minimise?

Answer: Conduction (since it

is made of an insulator) and Convection (since it does not allow convection current to transfer heat out of the flask)

Question 8

Hot substance

Styrofoam box

Styrofoam box is used to contain hot substances

because styrofoam is a good …………………

Answer: insulator

Question 9

Besides colour and texture, what are the

other factors that will affect the rate of heat

transfer by radiation?

Answer: Surface temperature and surface area

Question 10

What is the colour of the cooling fin?

Answer: Black

(Black is a good emitter of heat)

Question 11

Metal is the material used for cooling fin because it is a good …………………

Answer: conductor

Question 12 - True or False

Radiation of heat can take place without a medium

Answer: True

Question 13 - True or False

Convection of heat is caused by molecular vibration.

Answer: False

Convection is caused by density difference.Molecular vibration causes conduction of heat

Question 14 - True or False

Poor conductors are good insulators.

Answer: True

Question 15 - True or False

Gases are better conductor than solids.

Answer: False(Gas particles are very far apart hence it is difficult to

transfer heat by molecular vibration among the particles.)

Question 16 - True or False

Convection can take place in gas and liquid only.

Answer: True

Question 17 - True or False

Shiny surfaces are good absorber of heat.

Answer: False

Shiny surface will reflect heat hence it is a poor absorber of heat.

Question 18 - True or False

Black and rough surfaces are good

emitter of heat.

Answer: True

Question 19 - True or False

Hot tea in a black cup cools down faster than

hot tea in a white cup.

(Assuming the temperature of the tea in both cups are

the same and the material of the cups are the same.

Answer: True

Question 20 - True or False

Metals are better conductor than non-

metals.

Answer: True

(because metals have free electrons that helps in heat transfer by molecular vibration)