Heat Transfer MCQ Questions and Answers for Practice

1. Thermal diffusivity is

1. a dimensionless parameter
2. function of temperature
3. used as mathematical model
4. a physical property of the material

2. Which of the following has maximum value of thermal conductivity

1. aluminium
2. steel
3. brass
4. copper

3. Which of the following is the case of heat transfer by radiation

1. blast furnace
2. heating of building
3. cooling of parts in furnace
4. heat received by a person from fireplace

4. Sensible heat is the heat required to

1. change vapour into liquid
2. change liquid into vapour
3. increase the temperature of a liquid of vapour
4. convert water into steam and superheat it

5. Total heat is the heat required to

1. change vapour into liquid
2. change liquid into vapour
3. increase the temperature of a liquid or vapour
4. convert water into steam and superheat it

6. Thermal conductivity of glass-wool varies from sample to sample because of variation in

1. composition
2. density
3. porosity
4. all of the above.

7. When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by

1. conduction
2. convection
3. radiation
4. conduction and convection

8. When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by

1. conduction
2. convection
3. radiation
4. conduction and convection

9. When heat is Transferred by molecular collision, it is referred to as heat transfer by

1. conduction
2. convection
3. radiation
4. scattering

10. Heat transfer in liquid and gases takes place by

1. conduction
2. convection
3. radiation
4. conduction and convection

11. Heat flows from one body to other when they have

1. different heat contents
2. different specific heat
3. different atomic structure
4. different temperatures

12. The amount of heat flow through a body by conduction is

1. directly proportional to the surface area of the body
2. directly proportional to the temperature difference on the two faces of the body
3. dependent upon the material of the body
4. all of the above.

13. Thermal diffusivity of a substance is

1. directly proportional to thermal con¬ductivity
2. inversely proportional to density of substance
3. inversely proportional to specific heat
4. all of the above

14. Heat is transferred by all three modes of transfer, viz, conduction, convection and radiation in

1. electric heater
2. steam condenser
3. melting of ice
4. boiler.

15. Pick up the wrong case. Heat flowing from one side to other depends directly on

1. face area
2. time
3. thickness
4. temperature difference