## HEAT AND MASS TRANSFER MCQ

SECTION-2

##### Q31. Degree of saturation is defined as the ratio of

(a) specific humidity of moist air to the specific humidity of the saturated air at the same temperature
(b) mass of water vapour associated with unit mass of dry air to mass of water vapour associated with unit mass of dry air saturated at the same temperature
(c) any one of (a) and (b)
(d) none of the above.

Ans:(c) any one of (a) and (b)

(a) vs/va
(b)vs/(va+ vs)
(c) va/vs
(d)va/(va+ vs)

Ans:(c) va/vs

(a)ms/ma+ms
(b) ma/ma+ ms
(c)ms/ma
(d) ma/ms .

Ans:(c)ms/ma

##### Q34. Freon-12 has operating pressures of about

(a) 15 kg/cm2
(b) 30 kg/cm2
(c) 2 kg/cm2
(d) 8 kg/cm2

Ans:(d) 8 kg/cm2.

##### Q35. The temperature of air at which condensation of moisture begins when the air is cooled is known as

(a) dry bulb temperature
(b) dew point temperature
(c) wet bulb temperature
(d) saturation temperature.

Ans:(b) dew point temperature

##### Q36. The temperature of air recorded by an ordinary thermometer is known as

(a) dry bulb temperature
(b) dew point temperature
(c) wet bulb temperature
(d) saturation temperature.

Ans:(b) dew point temperature

##### Q37. The science which deals with the behaviour of mixture of air and water vapour is called

(a) psychrometry
(b) airconditioning
(c) hygrometry
(d) any one of (a) and (c)

Ans:(d) any one of (a) and (c)

##### Q38. The humidity ratio, mathematically, is equal to

(a) 0.622  ps /(p-ps )
(b)0.622  (p-ps )/ps
(c) 0.622 p/ps
(d)0.622 ×p/(p-ps )
where ps = Partial pressure of superheated water vapour, and p = Barometric pressure of mixture.

Ans:(a) 0.622  ps /(p-ps )

##### Q39. The relative humidity, mathematically, is equal to

(a) ps/pg
(b) vg/vs
(c) pg/ps
(d) any one of (a) and (b).
where ps = Actual partial pressure of superheated water vapour,
pg = Pressure at saturation corresponding to dry bulb temperature,
vg= Specific volume of vapour corresponding to saturated temperature, and
vs = Specific volume of vapour corresponding to pressure ps.

Ans:(d) any one of (a) and (b).

##### Q40. Absolute humidity is defined as

(a) actual mass of air in a unit volume of air and water vapour mixture
(b) actual mass of water vapour in a unit volume of air
(c) actual mass of water vapour in a unit volume of air and water vapour mixture
(d) actual mass of air in a unit volume of water vapour.

Ans:(b) actual mass of water vapour in a unit volume of air

2      3      4          6         8

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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