MCQ
921. Cooling water is required for following equipment in ammonia absorption plant-
condenser
evaporator
absorber
condenser, absorber and separator (rectifier)
922. The COP of refrigerator working on a reversed Carnot cycle is-
T1/T2-T1
T2-T1/T1
T1-T2/T1
T2/T2-T1
923. Most of the domestic refrigerators work on the following refrigeration system-.
vapour compression.
vapour absorption
Carnot cycle
electrolux refrigerator
924. A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be-
1.33
3.33
2.33
4.33
925. Reducing suction pressure in refrigeration cycle-.
lowers evaporation temperature
increases power required per ton of refrigeration
lowers compressor capacity because vapour is highter
reduces weight displaced by piston
all of the above
926. A heat pump working on a reversed Carnot cycle has a COP of 4. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be-
1KW
2kW
3kW
4kW
927. The COP of a vapor compression plant in comparison to vapor absorption plant is-
more
same
less
unpredictable
928. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is-.
same
less
more
unpredictable
929. The COP of a domestic refrigerator in comparison to domestic air conditioner will be--
same
less
more
unpredictable
930. The operating temperature of a cold storage is -4°C. The heat leakage from the surrounding is 30kW for the ambient temperature of 35°C. The actual COP of refrigeration plant used is one fourth that of ideal plant working between the same temperatures. The power required to drive the plant is-
1.86kW
7.44kW
3.72kW
21.74W
931. In a refrigeration cycle, the flow of refrigerant is controlled by-
Compressor
Condenser
Evaporator
Expansion valve
932. The evolution of heat of solution takes place in ammonia absorption plant when--
ammonia vapour goes into solution
ammonia vapour is driven out of solution
lithium bromide mixes with ammonia
weak solution mixes with strong solution
933. Vertical Laes on pressure-enthalpy chart show consent-
pressure lines
total heat lines
temperature lines
entropy lines
934. The relative coefficient of performance is equal to-
Theortical COP/Actual COP
Actual COP/Theortical COP
Actual COP x Theoretical COP
none of these
935. The COP of a refrigeration cycle with increase in evaporatour temperature, keeping condenser temperature constant will-.
decrease
increase
remain unaffected
unpredictable
936. The COP of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant will-
increase
decrease
unpredictable
remain unaffected
937. The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of COP-
more
equally
less
unpredictable
938. An ordinary passenger aircraft requires a cooling system of capacity-
2 TR
4TR
8TR
10 TR
939. The COP of a heat pump working on a reversed Carnot cycle is-
T1/T2-T1
T2-T1/T1
T1-T2/T1
T2/T2-T1
940. Which of the following refrigerants has lowest freezing point?
Freon-12
NH
CO
Freon-22