Refrigeration And Air Conditioning Mcqs Questions MCQs


refrigeration and air conditioning mcqs Questions

Total Questions : 1140

Page 1 of 57 pages
Question 1. When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be
  1.     Cooled and humidified
  2.     Cooled and dehumidified
  3.     Heated and humidified
  4.     Heated and dehumidified
Answer: Option A
Explanation :
Question 2. When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be
  1.     Cooled and humidified
  2.     Cooled and dehumidified
  3.     Heated and humidified
  4.     Heated and dehumidified
Answer: Option A
Explanation :
Question 3. The condition of refrigerant after passing through the condenser in a vapour compression system is
  1.     Saturated liquid
  2.     Wet vapour
  3.     Dry saturated vapour
  4.     Superheated vapour
Answer: Option A
Explanation :
Question 4. The boiling point of ________ is 10.5°c.
  1.     Ammonia
  2.     R-12
  3.     Sulphur dioxide
  4.     Carbon dioxide
Answer: Option C
Explanation :
Question 5. Pressure of water vapour is given by
  1.     0.622 Pv/ (Pb - Pv)
  2.     μ/[1 - (1 - μ) (Ps/Pb)]
  3.     [Pv (Pb - Pd)]/ [Pd (Pb - Pv)]
  4.     None of these
Answer: Option D
Explanation :
Question 6. A vapour absorption refrigerator uses _________ as a refrigerant.
  1.     Water
  2.     Ammonia
  3.     Freon
  4.     Aqua-ammonia
Answer: Option D
Explanation :
Question 7. Which of the following statement is wrong?
  1.     The performance of the vapour compression refrigerator varies considerably with both vaporising and condensing temperatures.
  2.     In vapour compression cycle, the useful part of the heat transfer is at the condenser.
  3.     In ammonia-hydrogen (Electrolux) refrigerator, no compressor, pump or fan is required.
  4.     The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance.
Answer: Option D
Explanation :
Question 8. In vapour compression refrigeration system, refrigerant occurs as liquid between
  1.     Condenser and expansion valve
  2.     Compressor and evaporator
  3.     Expansion valve and evaporator
  4.     Compressor and condenser
Answer: Option C
Explanation :
Question 9. In vapour compression refrigeration system, refrigerant occurs as liquid between
  1.     Condenser and expansion valve
  2.     Compressor and evaporator
  3.     Expansion valve and evaporator
  4.     Compressor and condenser
Answer: Option C
Explanation :
Question 10. Which of the following statement is wrong?
  1.     The performance of the vapour compression refrigerator varies considerably with both vaporising and condensing temperatures.
  2.     In vapour compression cycle, the useful part of the heat transfer is at the condenser.
  3.     In ammonia-hydrogen (Electrolux) refrigerator, no compressor, pump or fan is required.
  4.     The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance.
Answer: Option D
Explanation :
Question 11. Air refrigeration operates on
  1.     Carnot cycle
  2.     Reversed Carnot cycle
  3.     Rankine’s cycle
  4.     Brayton cycle
Answer: Option D
Explanation :
Question 12. The c.o.p. of a carnot refrigerator in winter will be _________ as compared to c.o.p. in summer.
  1.     Same
  2.     Lower
  3.     Higher
  4.     None of these
Answer: Option C
Explanation :
Question 13. The lowest thermal diffusivity is of
  1.     Iron
  2.     Lead
  3.     Aluminium
  4.     Rubber
Answer: Option D
Explanation :
Question 14. Which of the following statement is correct?
  1.     The human body can lose heat even if its temperature is less than the atmospheric temperature.
  2.     The increase in air movement increases the evaporation from the human body.
  3.     The warm air increases the rate of radiation of heat from the human body.
  4.     Both (A) and (B)
Answer: Option D
Explanation :
Question 15. The capillary tube, as an expansion device, is used in
  1.     Domestic refrigerators
  2.     Water coolers
  3.     Room air conditioners
  4.     All of these
Answer: Option D
Explanation :
Question 16. Air refrigeration cycle is used in
  1.     Domestic refrigerators
  2.     Commercial refrigerators
  3.     Air conditioning
  4.     Gas liquefaction
Answer: Option D
Explanation :
Question 17. The wet bulb depression indicates _________ humidity of the air.
  1.     Absolute
  2.     Relative
  3.     Specific
  4.     None of these
Answer: Option B
Explanation :
Question 18. The vapour pressure of refrigerant should be
  1.     Lower than atmospheric pressure
  2.     Higher than atmospheric pressure
  3.     Equal to atmospheric pressure
  4.     Could be anything
Answer: Option B
Explanation :
Question 19. The wet bulb temperature during sensible cooling of air
  1.     Remains constant
  2.     Increases
  3.     Decreases
  4.     None of these
Answer: Option C
Explanation :
Question 20. The c.o.p. of a refrigerator working on a reversed carnot cycle is (where t₁ = lowest absolute temperature, and t₂ = highest absolute temperature)
  1.     T₁ / (T₂ - T₁)
  2.     (T₂ - T₁)/T₁
  3.     (T₁ - T₂)/T₁
  4.     T₂/ (T₂ - T₁)
Answer: Option A
Explanation :