351. The expansion valve in a refrigerator controls the flow of refrigerant.
Correct
Incorrect
✅ The correct answer is option A.
Heat Transfer, Refrigeration and Air Conditioning MCQs
352. The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure, is called
humidity ratio
relative humidity
absolute humidity
degree of saturation
✅ The correct answer is option B.
353. The unit of Stefan-Boltzmann constant is
Watt/mK
Watt/m2K2
Watt/m2K4
Watt/mK2
✅ The correct answer is option C.
354. A perfect black body is one which
is black in colour
absorbs heat radiations of all wave lengths falling on it
reflects all the heat radiations
transmits the heat radiations
✅ The correct answer is option B.
355. During sensible cooling of air __________ decreases.
wet bulb temperature
relative humidity
dry bulb temperature
specific humidity
✅ The correct answer is option C.
356. The condition of refrigerant after leaving the compressor and before entering the condenser is superheated vapour.
Yes
No
✅ The correct answer is option A.
357. The wet bulb temperature lines, on the psychrometric chart, are curved lines.
TRUE
FALSE
✅ The correct answer is option B.
358. The relative humidity is defined as
the mass of water vapour present in 1 m3 of dry air
the mass of water vapour present in 1 kg of dry air
the ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
the ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
✅ The correct answer is option D.
360. According to Dalton’s law of partial pressures, (where pb = Barometric pressure, pa = Partial pressure of dry air, and pv = Partial pressure of water vapour)
Pb = pa – pv
Pb = pa + pv
Pb = pa x pv
Pb = pa/pv
✅ The correct answer is option B.