Heat and Mass Transfer Multiple Choice Questions

Heat and Mass Transfer

Question 1.

All radiations in a black body are

A.

 Reflected

B.

 Refracted

C.

 Transmitted

D.

 Absorbed

Explanation :

an object that absorbs all radiation falling on it, at all wavelengths, is called a black body. When a black body is at a uniform temperature, its emission has a characteristic frequency distribution that depends on the temperature. Its emission is called black-body radiation.

Question 2.

The heat is transferred by conduction, convection and radiation in

A.

 Melting of ice

B.

 Boiler furnaces

C.

 Condensation of steam in condenser

D.

 None of these

Explanation :

The heat is transferred by conduction, convection and radiation in Boiler Furnaces

Question 3.

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

A.

 Electric heater

B.

 Steam condenser

C.

 Boiler

D.

 Refrigerator condenser coils

Explanation :

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

Question 4.

The radiation emitted by a black body is known as

A.

 Black radiation

B.

 Full radiation

C.

 Total radiation

D.

 All of these

Explanation :

When a black body is at a uniform temperature, its emission has a characteristic frequency distribution that depends on the temperature. Its emission is called black-body radiation

Question 5.

The amount of heat flow through a body by conduction is

A.

 Directly proportional to the surface area of the body

B.

 Directly proportional to the temperature difference on the two faces of the body

C.

 Dependent upon the material of the body

D.

 All of the above

Explanation :

The amount of heat flow through a body by conduction is - Directly proportional to the surface area of the body - Directly proportional to the temperature difference on the two faces of the body - Dependent upon the material of the body