Heat Transfer MCQ Questions

Heat Transfer MCQ Questions for Competitive Examinations.

1-Thermal conductivity of solid metals ___ with rise in temperature.

(A) increases  

(B) decreases

(C) remains constant

(D) it depends upon the temperature

 

2-Thermal conductivity of non-metallic amorphous solids ___ with decrease in temperature.

(A) increases  

(B) decreases

(C) remains constant

(D) it depends upon the temperature

 

3-The heat required to ___ is known as Sensible heat.

(A) change vapor into liquid

(B) change liquid into vapor

(C) increase the temperature of a liquid or water

(D) convert water into steam and superheat it

 

4-The heat transferred by molecular collision, is referred to as

(A) conduction

(B) convection

(C) radiation

(D) conduction and convection

 

5-Following is an example of heat transfer by radiation.

(A) blast furnace

(B) heating of building

(C) cooling of parts in furnace

(D) heat received by a person from fireplace

 

6-Heat required to ___ is known Total heat.

(A) change vapor into liquid

(B) change liquid into vapor

(C) increase the temperature of a liquid or vapor

(D) convert water into steam and superheat it

 

7-Thermal conductivity of water ___ with rise in temperature.

(A) increases

(B) decreases

(C) remains constant

(D) depends upon the temperature

 

8-Thermal conductivity of air ___ with rise in temperature.

(A) increases

(B) decreases

(C) remains constant

(D) depends upon the temperature

 

9-Which one of the following has least conductivity?

(A) glass

(B) water

(C) rubber

(D) air

 

10-Which one of the following metal has highest thermal conductivity?

(A) aluminium

(B) steel

(C) brass

(D) copper

 

11-SI unit of thermal diffusivity is

(A) m2/sec

(B) m2/sec °C

(C) joule/m2 sec

(D) joule/m.sec °C

 

12-Which of the following dimensionless number is associated with natural convection heat transfer?

(A) Grashoff number

(B) Nusselt number

(C) Weber number

(D) Prandtl number

(E) Reynold number

 

13-The thermal diffusivity of solid is generally

(A) less than that for gas

(B) less than that for liquid

(C) more than that for liquid and gas

(D) more or less same as for liquid and gas

 

14-Heat pipe acts as

(A) an insulator

(B) conductor and insulator

(C) a superconductor

(D) a fin

 

15-The amount of radiation depends upon

(A) nature of body

(B) temperature of body

(C) surface type

(D) all of the above

 

16-The emissive power of a body depends upon

(A) its temperature

(B) its wave length

(C) its physical nature

(D) all of the above

 

17- (energy absorbed by the body / total energy falling on it) =

(A) absorptive power

(B) emissive power

(C) absorptivity

(D) emissivity

 

ANSWERS:

1-(B), 2-(B), 3-(C), 4-(B), 5-(D), 6-(D), 7-(D), 8-(A), 9-(D), 10-(D), 11-(A), 12-(A), 13-(C), 14-(B), 15-(D), 16-(D), 17-(A)