71. The coefficient of performance is the ratio of the refrigerant effect to the
A.Heat of compression
B.Work done by compressor
C.Enthalpy increase in compressor
D.All of the above

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72. The C.O.P. of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will
A.Increase
B.Decrease
C.Remain unaffected
D.May increase or decrease depending on the type of refrigerant used

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73. Vertical lines on pressure-enthalpy chart show constant
A.Pressure lines
B.Temperature lines
C.Total heat lines
D.Entropy lines

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74. Most of the domestic refrigerators work on the following refrigeration system
A.Vapour compression
B.Vapour absorption
C.Carnot cycle
D.Electrolux refrigerator

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75. 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

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76. Reducing suction pressure in refrigeration cycle
A.Lowers evaporation temperature
B.All of the above.
C.Lowers compressor capacity because vapour is lighter
D.Reduces weight displaced by piston

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77. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is
A.Same
B.More
C.Less
D.More or less depending on ambient conditions

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