## HEAT AND MASS TRANSFER MCQ

SECTION-3

##### Q71. Choose the correct statement

(c) The reciprocal of thermal resistance is known as thermal conductance.
(d) The unit of thermal conductivity in S.I. system is W/m2 K.

Ans:(c) The reciprocal of thermal resistance is known as thermal conductance.

##### Q72. In a vapour compression cycle, the refrigerant is in the form of superheated vapour before passing through

(a) condenser
(b) evaporator
(c) compressor
(d) throttle valve.

Ans:(a) condenser

##### Q73. In a vapour compression cycle, the refrigerant is the form of dry saturated vapour before entering

(a) condenser
(b) evaporator
(c) compressor
(d) throttle valve.

Ans:(c) compressor

##### Q74. A domestic refrigerator has the co-efficient of performance

(a) equal to 1.0
(b) less than 1.0
(c) more than 1.0
(d) any value.

Ans:(c) more than 1.0

##### Q75. The process which transmits energy by means of electromagnetic waves is called

(a) convection
(c) conduction
(d) none of the above.

##### Q76. The amount of radiation depends upon

(a) temperature of the body only
(b) surface area of the body only
(c) nature of the body only
(d) all of the above.

Ans:(c) nature of the body only

##### Q77. Radiant energy, being electromagnetic in character

(a) needs medium for its propagation
(b) needs no medium
(c) needs heating before propagation
(d) none of the above.

Ans:(b) needs no medium

##### Q78. The coefficient of thermal conductivity is defined as the heat flow per unit time

(a) through unit thickness
(b) when temperature difference of unity is maintained between opposite faces
(c) when temperature gradient is unity
(d) across unit area when temperature gradient is unity.

Ans:(d) across unit area when temperature gradient is unity.

##### Q79. The thermal conductivity in MKS units is expressed as

(a) kcal/hr mºC
(b) kcal/hr m2 ºC
(c) kcal/mºC
(d) kcal/hr m3ºC.

Ans:(a) kcal/hr mºC

##### Q80. The thermal conductivity in S.I. units is expressed as

(a) J/m2 K
(b) W/m K
(c) W/m K sec
(d) Wm/m K.

Ans:(b) W/m K

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##### Read More Sections of Heat Transfer and Mass Transfer

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Heat and Mass Transfer, RAC  MCQ – Section-1

Heat and Mass Transfer, RAC  MCQ – Section-2

Heat and Mass Transfer, RAC  MCQ – Section-3

Heat and Mass Transfer, RAC  MCQ – Section-4