Refrigeration and Air-Conditioning Multiple Choice Questions with Answers - Set 03 - ObjectiveBooks

Refrigeration and Air-Conditioning Multiple Choice Questions with Answers - Set 03

Practice Test: Question Set - 03

1. The vapour pressure of refrigerant should be
    (A) Lower than atmospheric pressure
    (B) Higher than atmospheric pressure
    (C) Equal to atmospheric pressure
    (D) Could be anything

2. Which of the following statement is wrong?
    (A) The performance of the vapour compression refrigerator varies considerably with both vaporising and condensing temperatures.
    (B) In vapour compression cycle, the useful part of the heat transfer is at the condenser.
    (C) In ammonia-hydrogen (Electrolux) refrigerator, no compressor, pump or fan is required.
    (D) The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance.

3. In a vapour compression system, the condition of refrigerant before passing through the condenser is
    (A) Saturated liquid
    (B) Wet vapour
    (C) Dry saturated vapour
    (D) Superheated vapour

4. For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then
    (A) Bigger cabinet should be used
    (B) Smaller cabinet should be used
    (C) Perfectly tight vapour seal should be used
    (D) Refrigerant with lower evaporation temperature should be used

5. During sensible heating of air _________ decreases.
    (A) Wet bulb temperature
    (B) Relative humidity
    (C) Dry bulb temperature
    (D) Specific humidity

6. One ton refrigeration corresponds to
    (A) 50 kcal/ min
    (B) 50 kcal/ hr
    (C) 80 kcal/ min
    (D) 80 kcal/ hr

7. The process, generally used in winter air-conditioning to warm and humidity the air, is called
    (A) Humidification
    (B) Dehumidification
    (C) Heating and humidification
    (D) Cooling and dehumidification

8. 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
    (D) Smelling

9. The reduced ambient air cooling system has
    (A) One cooling turbine and one heat exchanger
    (B) One cooling turbine and two heat exchangers
    (C) Two cooling turbines and one heat exchanger
    (D) Two cooling turbines and two heat exchangers

10. In vapour compression cycle, the condition of refrigerant is saturated liquid
    (A) After passing through the condenser
    (B) Before passing through the condenser
    (C) After passing through the expansion throttle valve
    (D) Before entering the expansion valve

11. Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?
    (A) Ammonia
    (B) Carbon dioxide
    (C) Sulphur dioxide
    (D) Fluorine

12. If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be
    (A) Same
    (B) More
    (C) Less
    (D) More/less depending on rating

13. Hydrogen is used in Electrolux refrigeration system so as to _________ the rate of evaporation of the liquid ammonia passing through the evaporator.
    (A) Equalize
    (B) Reduce
    (C) Increase
    (D) None of these

14. Pick up the wrong statement. A refrigerant should have
    (A) Tow specific heat of liquid
    (B) High boiling point
    (C) High latent heat of vaporisation
    (D) Higher critical temperature

15. The pressure at the inlet of a refrigerant compressor is called
    (A) Suction pressure
    (B) Discharge pressure
    (C) Critical pressure
    (D) Back pressure

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