Heat Transfer MCQ Questions and Answers for Practice

1. Thermal diffusivity is

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

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

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

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

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

4. Sensible heat is the heat required to

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

5. Total heat is the heat required to

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

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

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

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 and convection
2. conduction
3. convection
4. radiation

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 and convection
2. conduction
3. convection
4. radiation

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

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

10. Heat transfer in liquid and gases takes place by

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

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

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

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

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

13. Thermal diffusivity of a substance is

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

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

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

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

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