## HEAT AND MASS TRANSFER MCQ

SECTION-1

##### Q11. The essential condition for the transfer of heat from one body to another is

(a) both bodies must be in physical contact
(b) heat content of one body must be more than that of the other
(c) one of the bodies must have a high value of thermal conductivity
(d) there must exist a temperature difference between the bodies.

Ans:(d) there must exist a temperature difference between the bodies.

##### Q12. Gas turbines work on

(a) constant volume cycle
(b) constant pressure cycle
(c) constant temperature cycle
(d) constant enthalpy cycle.

Ans:(b) constant pressure cycle

##### Q13. The radial heat transfer rate through hollow cylinder increases as the ratio of outer radius to inner radius

(a) decreases
(b) increases
(c) constant
(d) none of the above.

Ans:(a) decreases

##### Q14. Stefan-Boltzmann law is expressed as

(a) Q = σ AT4
(b) Q = σ A2T4
(c) Q = σ AT2
(d) Q = AT4 .

Ans:(a) Q = σ AT4

(a) Freon-12
(b) NH3
(c) CO2
(d) Air.

Ans:(b) NH3

##### Q16. Ammonia is preferred as a refrigerant in large commercial installations because

(a) it is non-toxic
(b) it has low latent heat
(c) it has low working pressure
(d) it is relatively cheap.

Ans:(c) it has low working pressure

##### Q17. For a cylindrical rod with uniformly distributed heat sources, the thermal gradient dt/dr at half the radius location will be

(a) one-fourth of that at the surface
(b) one-half of that at the surface
(c) twice of that at the surface
(d) four times of that at the surface.

Ans:(b) one-half of that at the surface

##### Q18. For steady state heat flow and constant value of thermal conductivity, the temperature distribution for a plane wall is a

(a) linear
(b) parabolic
(c) logarithmic
(d) exponential curve.

Ans:(a) linear

##### Q19. In an adiabatic saturation process

(a) the enthalpy remains constant
(b) the temperature remains constant
(c) the absolute humidity remains constant
(d) the relative humidity remains constant.

Ans:(a) the enthalpy remains constant

##### Q20. Critical thickness of insulation for spheres is given by

(a) k/h
(b) k/4π h
(c) h/2k
(d) 2k/h.

where k is the coefficient of thermal conductivity and h is convective heat transfer coefficient.

Ans:(d) 2k/h.

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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