561. In a refrigeration cycle, the flow of refrigerant is controlled by___________________?
D. expansion valve
E. all of the above
562. The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents_____________________?
A. condensation of the refrigerant vapour
B. evaporation of the refrigerant liquid
C. compression of the refrigerant vapour
D. metering of the refrigerant liquid
E. none of the above
563. Freon group of refrigerants are___________________?
C. non-inflammable and toxic
D. non-toxic and inflammable
E. non-toxic and non-inflammable
564. In vapour compression cycle using NH3 as refrigerant, initial charge is filled at_________________?
A. suction of compressor
B. delivery of compressor
C. high pressure side close to receiver
D. low pressure side near receiver
E. anywhere in the cycle
565. On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process ________________?
A. involves no change in volume
B. takes place at constant temperature
C. takes place at constant entropy
D. takes place at constant enthalpy
E. takes place at constant pressure
566. 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
E. sensing reduction in pressure
567. Moisture in freon refrigeration system causes________________?
A. ineffective refrigeration
B. high power consumption
C. freezing automatic regulating valve
D. corrosion of whole system
E. breakdown of refrigerant
568. Super heating in a refrigeration cycle __________________?
A. increases COP
B. decreases COP
C. COP remains unaltered
D. other factors decide COP
569. For obtaining high COP, the pressure range of compressor should be_______________?
D. any value
E. there is no such criterion
570. The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will______________________?
C. remain unaffected
D. may increase or decrease depending on the type of refrigerant used