REFRIGERATION and AIR CONDITIONING MCQ
21.The optimum effective temperature for human comfort is
A. Higher in winter than in summer
B. Lower in winter than in summer
C. Same in winter and summer
D. Not dependent on season
22.An evaporator is also known as
A. Freezing coil
B. Cooling coil
C. Chilling coil
D. All of these
23.In a refrigeration cycle, the flow of refrigerant is controlled by
A. Compressor
B. Condenser
C. Evaporator
D. Expansion valve
24.Vapour compression refrigeration is somewhat like
A. Carnot cycle
C. Reversed Carnot cycle
D. None of the above
25.At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant
A. decreases
B. increases
C. remains same
D. depends on other factors
26.A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of -23°C. The Carnot coefficient of performance of cycle will be
A.0.2
B.1.2
C.5
D.6
27.The bypass factor (B. P. F.) in case of sensible heating of air is (Where td₁ = Dry bulb temperature of air entering the heating coil, td₂ = Dry bulb temperature of air leaving the heating coil, and td₃ = Dry bulb temperature of heating coil)
A.(td₂ – td₃)/(td₃ – td₁)
B.(td₃ – td₂)/(td₃ – td₁)
C.(td₃ – td₁)/(td₂ – td₃)
D.(td₃ – td₁)/(td₃ – td₂)
28.The general rule for rating refrigeration systems (excepting for CO₂ system) is to approximate following h.p. per ton of refrigeration
A.0.1 to 0.5 h.p. per ton of refrigeration
B.0.5 to 0.8 h.p. per ton of refrigeration
C.1 to 2 h.p. per ton of refrigeration
D.2 to 5 h.p. per ton of refrigeration
29.The freezing point of R-12 is
A.-86.6°C
B.-95.2°C
C.-107.7°C
D.-135.8°C
30.The coefficient of performance (C.O.P.) of a refrigerator working as a heat pump is given by
A.(C.O.P.)P = (C.O.P.)R + 2
B.(C.O.P.)P = (C.O.P.)R + 1
C.(C.O.P)P = (C.O.P)R – 1
D.(C.O.P)P = (C.O.P)R