1. Physics Quiz Thermal Heat Transfer

2. Question 1
What is the method of heat transfer from the heater to the metal plate?
Answer: Radiation

3. Question 2
What is the method of heat transfer from the metal plate to the wax?
Answer: Conduction

4. Question 3
What is the method of heat transfer from the wax to the cork?
Answer: Conduction

5. 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.

6. Question 5
Which heat transfer method(s) will the vacuum layer of the thermal flask help to minimise?
Answer: Conduction and
Convection

7. Question 6
Which heat transfer method(s) will the silvered wall of the thermal flask help to minimise?
Answer: Radiation

8. Question 7
Which 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)

9. Question 8
Hot substance
Styrofoam box
Styrofoam box is used to contain hot substances because styrofoam is a good …………………
Answer: insulator

10. 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

11. Question 10 What is the colour of the cooling fin? Answer: Black
(Black is a good emitter of heat)

12. Question 11
Metal is the material used for cooling fin because it is a good …………………
Answer: conductor

13. Question 12 - True or False
Radiation of heat can take place without a medium
Answer: True

14. 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

15. Question 14 - True or False
Poor conductors are good insulators.
Answer: True

16. 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.)

17. Question 16 - True or False
Convection can take place in gas and liquid only.
Answer: True

18. 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.

19. Question 18 - True or False
Black and rough surfaces are good emitter of heat.
Answer: True

20. 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

21. 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)