Refrigeration and Air Conditioning 3

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Refrigeration and Air Conditioning 3

Part 3: List for questions and answers of Refrigeration and Air Conditioning

Q1. In vapour compression cycle the highest temperature of the refrigerant during the cycle occurs
a) After expansion valve
b) After evaporator
c) After condenser
d) After compression

Q2. During compression in a vapour compression cycle of the refrigerant is super heated
a) C.O.P. is reduced
b) C.O.P. is increased
c) Refrigerating effect is reduced
d) None of the above

Q3. Dry bulb temperature depends on
a) Humidity of air
b) Water vapour content of air
c) Condition of air
d) None of the above

Q4. The heat removed capacity of a one ton refrigerator is
a) 100 kcal/4 hour
b) 100 kcal/hour
c) 50 kcal/min
d) None of the above

Q5. A refrigerating system operates on the reversed Carnot cycle. The higher temperature of the refrigerant in the system is 40 degree C and the lower is – 15 degree C. The capacity is to be 10 tons. Neglecting all losses, the coefficient of performance of the system would be
a) 2.67
b) 3.75
c) 4.69
d) 7.36

Q6. No refrigerator using reversed Carnot cycle has been constructed because
a) It is less efficient
b) It requires bulky machines
c) It is uneconomical
d) Isentropic portions of cycle require low speeds whereas isothermal protons require high speeds

Q7. In a domestic refrigerator if the compressor runs continuously, it shows that
a) The system is working perfectly all right
b) The refrigeration is to full capacity
c) The system is overloaded
d) None of the above

Q8. If the compressor of a refrigeration system is noisy, it shows that
a) Compressor drive coupling is loose
b) Lack of oil
c) Compressor or motor loose on base
d) Any of the above

Q9. If a discharge pressure of a refrigeration compressor is too high, it shows there is (are)
a) Too little or too warm condenser water
b) Fouled tubes in shell and tube condenser
c) Improper operations of evaporator condenser
d) Any of the above

Q10. If the discharge pressure of refrigeration compressor is too high it shows
a) Too little or to warm condenser water
b) Lack of refrigerant
c) Excessive cooling load
d) Any of the above

Q11. If the suction pressure of a refrigeration compressor is too high, it shows
a) Lack of refrigerant on cycle
b) Excessive load and evaporator
c) Negligible load on evaporator
d) None of the above

Q12. If a one ton refrigeration machine, the significance of term “One ton” is that
a) One ton of refrigerant is used
b) One ton water can be stored at a time
c) One ton of water can be converted into ice
d) One ton of ice when melts from and at 0 degree C in 24 hours the refrigeration effect equivalent to that

Q13. A Bell-Coleman cycle is
a) Reversed Carnot cycle
b) Reversed Joule cycle
c) Reversed Otto cycle
d) Reversed Sterling cycle

Q14. In a refrigerating system work done per kg of air is 20 kcal and heat extracted per kg of air is 25 kcal. The quantity of refrigerant used is 10 kg. The coefficient of performance of the system would be
a) 0.8
b) 8
c) 1.25
d) 5

Q15. In a vapour compression cycle the vapour as it leaves the compressor is
a) In liquid form
b) Dry vapour
c) Dry and saturated vapour
d) None of the above

Q16. In a vapour compression cycle the refrigerant immediately after expansion valve is in
a) Liquid form
b) Wet vapour form
c) Dry vapour form
d) None of the above

Q17. The ability of an evaporator to absorb heat does not depends on
a) Its size, surface condition and material
b) Kind of refrigerant used
c) Temperature difference between the evaporator and the surrounding air
d) Velocity of turbulence

Q18. A condenser removes from the refrigerant
a) Sensible heat only
b) Latent heat only
c) Sensible heat and latent heat
d) Partly sensible heat and latent heat

Q19. A critical temperature is the temperature
a) Below which gas is always liquefied
b) Above which a gas will never be liquefied
c) Below which a gas does not obey gas laws
d) None of the above

Q20. The critical pressure of a liquid is the pressure
a) Below which a liquid will always be in vapour form
b) Above which a liquid will remain a liquid
c) Above which a liquid will always turn into a vapour
d) None of the above

Part 3: List for questions and answers of Refrigeration and Air Conditioning

Q1. Answer: d

Q2. Answer: a

Q3. Answer: d

Q4. Answer: c

Q5. Answer: c

Q6. Answer: c

Q7. Answer: c

Q8. Answer: d

Q9. Answer: d

Q10. Answer: b

Q11. Answer: b

Q12. Answer: d

Q13. Answer: b

Q14. Answer: b

Q15. Answer: c

Q16. Answer: b

Q17. Answer: b

Q18. Answer: a

Q19. Answer: b

Q20. Answer: b