Refrigeration and Air Conditioning 2

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Refrigeration and Air Conditioning 2

Part 2: List for questions and answers of Refrigeration and Air Conditioning

Q1. Oil separator in a refrigeration cycle is installed
a) Before compressor
b) Between compressor and condenser
c) Between condenser and evaporator
d) Could be installed anywhere

Q2. The leaks of refrigerant from a cycle may be detected by
a) Halide torch test
b) Sulphur candle test
c) Soap and water test
d) Any of above

Q3. In halide torch test if there is leakage of refrigerant, the colour of flame with change to
a) Yellow
b) Red or pink
c) Violet or orange
d) Blue or bright green

Q4. Moisture in Freon refrigeration system causes
a) Ineffective refrigeration
b) Damage to compressor
c) Freezing of automatic regulating valve
d) None of the above

Q5. In a refrigerator system if compressor fails to operate, the probable reason could be
a) Low voltage
b) Burnt motor
c) Fuse blown
d) Any of the above

Q6. In a refrigeration system, if the compressor short cycles, the probable cause could be
a) Intermittent contact in electric control circuit
b) Dirty or iced evaporator
c) Over change of refrigerant
d) Any of the above

Q7. The condition of refrigerant before and after the condenser in a vapour compression cycle is
a) Dry saturated, saturated liquid
b) Dry saturated, wet vapour
c) Wet vapour, wet vapour
d) Liquid, liquid

Q8.In electrolyse refrigerator
a) Ammonia is absorbed in water
b) Ammonia is absorbed in hydrogen
c) Ammonia evaporates in hydrogen
d) Hydrogen evaporates in ammonia

Q9. In case of Freon as refrigerant the pipe lines should be of
a) Copper
b) Seamless steel tubes
c) Stainless steel tubes
d) None of the above

Q10. Frost on cooling coils
a) Increases heat transfer
b) Improves COP of the system
c) Reduces evaporator temperature
d) Acts as an insulation, increasing power consumption

Q11. Defrosting in a refrigerator may be done by
a) Stopping the compressor for a while
b) Placing trays of warm water in the refrigerator
c) Any of the above
d) None of the above

Q12. A thermometer installed, in a vapour compression ammonia system, after the condenser shows elevated reading than the normal. It shows that
a) Condenser needs cleaning
b) Uneven water distribution over the condensing surfaces
c) Any of the above
d) None of the above

Q13. In ammonia vapour compression system the temperature rise between the condenser outlet and the expansion valve should be
a) As high as possible to improve the performance
b) As little as possible for better performance
c) Anything as it has no bearing on the performance of system
d) None of the above

Q14. In a vapour compression refrigeration cycle using ammonia as a refrigerant the temperature of ammonia after compression will be at the range
a) 15°C – 40°C
b) 0°C – 15°C
c) 40°C – 0°C
d) 70°C – 110°C

Q15. In a vapour compression cycle the lowest temperature occurs in
a) Compressor
b) Expansion valve
c) Condenser
d) Evaporator

Q16. The most common type of vapour absorption system in use for industrial application is
a) Freon 12 and water
b) Ammonia and water
c) Brine and water
d) Hydrogen and water

Q17. In a vapour absorption system as compared to vapour compression system, the compressor is replaced by
a) Evaporator
b) Receiver
c) Condenser
d) Absorber and generator

Q18. The moisture in a refrigeration system is removed by
a) Driers
b) Dehumidifiers
c) Evaporators
d) None of the above

Q19. A refrigerant with lowest freezing point temperature is
a) Freon 11
b) Freon 12
c) Freon 22
d) Carbon dioxide

Q20. The condition of refrigerant before and after compression in vapour compression cycle is
a) Wet vapour, cry saturated vapour
b) Liquid, wet vapour
c) Dry saturated vapour, superheated vapour
d) Wet vapour, wet vapour

Part 2: List for questions and answers of Refrigeration and Air Conditioning

Q1. Answer: b

Q2. Answer: d

Q3. Answer: d

Q4. Answer: c

Q5. Answer: d

Q6. Answer: d

Q7. Answer: a

Q8. Answer: c

Q9. Answer: b

Q10. Answer: d

Q11. Answer: c

Q12. Answer: c

Q13. Answer: b

Q14. Answer: d

Q15. Answer: d

Q16. Answer: b

Q17. Answer: d

Q18. Answer: a

Q19. Answer: c

Q20. Answer: a