REFRIGERATION and AIR CONDITIONING MCQ
11.During cooling and dehumidification, dry bulb temperature
A. Remains constant
B. Increases
C. Decreases
D. No one of these
12.In a domestic vapour compression refrigerator, the refrigerant commonly used is
A.CO?
B. Ammonia
C.R-12
D. All of these
13.In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be
A. High, of the order of 25°
B.As low as possible (3 to 11°C)
C. Zero
D. Any value
14.The minimum temperature to which water can be cooled in a cooling tower is
A. Dew point temperature of air
B. Wet bulb temperature of air
C. Dry bulb temperature of air
D. Ambient air temperature
15.Air refrigeration cycle is used in
A. Domestic refrigerators
B. Commercial refrigerators
C. Air conditioning
D. Gas liquefaction
16.The value of C.O.P in vapour compression cycle is usually
A. Always less than unity
B. Always more than unity
C. Equal to unity
D. Any one of the above
17.The specific humidity during cooling and dehumidification
A. Remains constant
B. Increases
C. Decreases
D. None of these
18.The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is
A. Bigger
B. Smaller
C. Equal
D. Smaller/bigger depending on capacity
19.In a vapour compression refrigeration system, a throttle valve is used in place of an expander because
A. It considerably reduces mass of the system
B. It improves the C.O.P., as the condenser is small
C. The positive work in isentropic expansion of liquid is very small
D. It leads to significant cost reduction
20.In a refrigeration system, heat absorbed in comparison to heat rejected is
A. More
B. Less
C. Same
D. More for small capacity and less for high capacity
