Multiple choice questions on Refrigeration and air conditioning - Set 13 - ObjectiveBooks
Multiple choice questions on Refrigeration and air conditioning - Set 13

Multiple choice questions on Refrigeration and air conditioning - Set 13

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Practice Test: Question Set - 13

1. Efficiency of a Carnot engine is given as 80%. If the cycle direction be reversed, what will be the value of C.O.P. of reversed Carnot Cycle?
    (A) 1.25
    (B) 0.8
    (C) 0.5
    (D) 0.25
2. The refrigerant supplied to a compressor must be
    (A) Superheated vapour refrigerant
    (B) Dry saturated liquid refrigerant
    (C) A mixture of liquid and vapour refrigerant
    (D) None of these
3. One of the purposes of sub cooling the liquid refrigerant is to
    (A) Reduce compressor overheating
    (B) Reduce compressor discharge temperature
    (C) Increase cooling effect
    (D) Ensure that only liquid and not the vapour enters the expansion (throttling) valve
4. The ratio of heat extracted in the refrigerator to the work-done on the refrigerant is called
    (A) Coefficient of performance of refrigeration
    (B) Coefficient of performance of heat pump
    (C) Relative coefficient of performance
    (D) Refrigerating efficiency
5. In vapour compression cycle the condition off refrigerant is dry saturated vapour
    (A) After passing through the condenser
    (B) Before passing through the condenser
    (C) After passing through the expansion or throttle valve
    (D) Before entering the compressor
6. In larger industrial and commercial reciprocating compression systems, refrigerant widely used is
    (A) Ammonia
    (B) Carbon dioxide
    (C) Sulphur dioxide
    (D) R-12
7. In vapour compression cycle the condition of refrigerant is superheated vapour
    (A) After passing through the condenser
    (B) Before passing through the condenser
    (C) After passing through the expansion or throttle valve
    (D) Before entering the expansion valve
8. In which of the following refrigeration system, waste heat can be effectively used?
    (A) Vapour compression cycle
    (B) Vapour absorption cycle
    (C) Air refrigeration cycle
    (D) None of these
9. Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system
    (A) Strong solution to weak solution
    (B) Weak solution to strong solution
    (C) Strong solution to ammonia vapour
    (D) Ammonia vapours to weak solution
10. The material of pipe lines for a system using Freon as a refrigerant should be
    (A) Brass
    (B) Copper
    (C) Steel
    (D) Aluminium
11. Ammonia is
    (A) Non-toxic
    (B) Non-inflammable
    (C) Toxic and non-inflammable
    (D) Highly toxic and inflammable
12. The sensible heat factor during cooling and dehumidification process is given by (where h₁ = Enthalpy of air entering the cooling coil, h₂ = Enthalpy of air leaving the cooling coil, and hA = Enthalpy of air at the end of dehumidification process)
    (A) (hA - h2)/ (h1 - h2)
    (B) (h2 - hA)/ (h1 - h2)
    (C) (h1 - h2)/ (hA - h2)
    (D) (hA - h1)/ (h2 - h1)
13. Most of the domestic refrigerators work on the following refrigeration system
    (A) Vapour compression
    (B) Vapour absorption
    (C) Carnot cycle
    (D) Electrolux refrigerator
14. For unsaturated air, the dew point temperature is __________ wet bulb temperature.
    (A) Equal to
    (B) Less than
    (C) More than
    (D) None of these
15. Air refrigeration cycle is used in
    (A) Domestic refrigerators
    (B) Commercial refrigerators
    (C) Air conditioning
    (D) Gas liquefaction
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