191. In a vapour compression system, the condition of refrigerant is dry saturated vapour
before entering the compressor
after leaving the compressor
before entering the condenser
after leaving the cond
✅ The correct answer is option A.
Heat Transfer, Refrigeration and Air Conditioning MCQs
192. Carbon dioxide is
colourless
odourless
non-flammable
all of these
✅ The correct answer is option D.
193. The unit of overall coefficient of heat transfer is
W/m2K
W/m2
W/mK
W/m
✅ The correct answer is option A.
195. The ratio of heat extracted in the refrigerator to the workdone on the refrigerant is called
coefficient of performance of refrigeration
coefficient of performance of heat pump
relative coefficient of performance
refrigerating efficien
✅ The correct answer is option A.
196. The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number)n, where n is equal to
-0.33333333333333
-0.66666666666667
1
-1
✅ The correct answer is option A.
197. An evaporator is also known as
freezing coil
cooling coil
chilling coil
all of these
✅ The correct answer is option D.
198. The undesireable property of a refrigerant is
non-toxic
non-flammable
non-explosive
high boiling point
✅ The correct answer is option D.
199. In larger industrial and commercial reciprocating compression systems, refrigerent widely used is
ammonia
carbon dioxide
sulphur dioxide
R-12
✅ The correct answer is option A.
200. When the lower temperature of a refrigerating machine is fixed, then the coefficient of performance can be improved by
operating the machine at higher speeds
operating the machine at lower speeds
raising the higher temperature
lowering the higher te
✅ The correct answer is option D.