Refrigeration and air conditioning practice exam - Set 12 - ObjectiveBooks

# Practice Test: Question Set - 12

1. In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperature
(A) Which lies between the dry bulb and wet bulb temperatures of the incoming stream
(B) Which lies between the wet bulb and dew point temperatures of the incoming stream
(C) Which is lower than the dew point temperature of the incoming stream
(D) Of adiabatic saturation of incoming stream

2. Superheating in a refrigeration cycle
(A) Increases C.O.P
(B) Decreases C.O.P
(C) C.O.P remains unaltered
(D) Other factors decide C.O.P

3. The specific humidity during cooling and dehumidification
(A) Remains constant
(B) Increases
(C) Decreases
(D) None of these

4. Chaperon equation is applicable for registration at
(A) Saturation point of vapour
(B) Saturation point of liquid
(C) Sublimation temperature
(D) Triple point

5. For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of
(A) Copper
(B) Aluminium
(C) Steel
(D) Brass

6. The refrigerant for a refrigerator should have
(A) High sensible heat
(B) High total heat
(C) High latent heat
(D) Low latent heat

7. The bypass factor for a cooling coil
(A) Increases with increase in velocity of air passing through it
(B) Decreases with increase in velocity of air passing through it
(C) Remains unchanged with increase in velocity of air passing through it
(D) May increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering

8. Accumulators should have adequate volume to store refrigerant charge at least
(A) 10%
(B) 25%
(C) 50%
(D) 75%

9. The dry bulb temperature lines, on the psychrometric chart are
(A) Vertical and uniformly spaced
(B) Horizontal and uniformly spaced
(C) Horizontal and non-uniformly spaced
(D) Curved lines

10. In S.J. unit, one ton of refrigeration is equal to
(A) 210 kJ/ min
(B) 21 kJ/ min
(C) 420 kJ/ min
(D) 840 kJ/ min

11. The cooling system used for supersonic aircrafts and rockets is
(A) Simple air cooling system
(B) Bootstrap air cooling system
(C) Reduced ambient air cooling system
(D) Regenerative air cooling system

12. Short horizontal lines on pressure-enthalpy chart show
(A) Constant pressure lines
(B) Constant temperature lines
(C) Constant total heat lines
(D) Constant entropy lines

13. Which of the following statement is wrong?
(A) The value of C.O.P. is always greater than one
(B) In a vapour compression system, the condition of refrigerant before entering the compressor is dry saturated vapour
(C) The space between the saturated liquid line and saturated vapour line, in a pressure enthalpy chart, is wet vapour region
(D) None of the above

14. One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice
(A) In 1 hour
(B) In 1 minute
(C) In 24 hours
(D) In 12 hours

15. In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by
(A) Liquid pump
(B) Generator
(C) Absorber and generator
(D) Absorber, generator and liquid pump

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