REFRIGERATION and AIR CONDITIONING MCQ-2
31.The wet bulb temperature during sensible heating of air
A. Remains constant
B. Increases
C. Decreases
D. None of these
32.The C.O.P. of a refrigerator working on a reversed Carnot cycle is (where T₁ = Lowest absolute temperature, and T₂ = Highest absolute temperature)
A.T₁ / (T₂ – T₁)
B.(T₂ – T₁)/T₁
C.(T₁ – T₂)/T₁
D.T₂/ (T₂ – T₁)
33.The relative coefficient of performance is equal to
A.(Theoretical C.O.P.)/ (Actual C.O.P.)
B.(Actual C.O.P.) /(Theoretical C.O.P.)
C.(Actual C.O.P.) × (Theoretical C.O.P.)
D. None of these
34.If a gas is to be liquefied, its temperature must be
A. Increased to a value above its critical temperature
B. Reduced to a value below its critical temperature
C. Equal to critical temperature
D. None of the above
35.The advantage of dry compression is that
A. It permits higher speeds to be used
B. It permits complete evaporation in the evaporator
C. It results in high volumetric and mechanical efficiency
D. All of the above
36.The leaks in a refrigeration system using Freon are detected by
A. Halide torch which on detection produces greenish flame lighting
B. Sulphur sticks which on detection gives white smoke
C. Using reagents
D. Smelling
37.The higher temperature in vapour compression cycle occurs at
A. Receiver
B. Expansion valve
C. Evaporator
D. Compressor discharge
38.Highest temperature encountered in refrigeration cycle should be
A. Near critical temperature of refrigerant
B. Above critical temperature
C. At critical Temperature
D. Much below critical temperature
39.In actual air-conditioning applications for R-12 and R-22, and operating at a condenser temperature of 40° C and an evaporator temperature of 5° C, the heat rejection factor is about
A.1
B.1.25
C.2.15
D.5.12
40.The capillary tube is not used in large capacity refrigeration systems because
A. Cost is too high
B. Capacity control is not possible
C. It is made of copper
D. Required pressure drop cannot be achieved
