MCQ on refrigeration and Air conditioning for JE EXAM part 2
| 11. Which of the following refrigerants is used for refrigeration in airplanes? |
(c) CO2 (d) NH3
| Ans. (b) |
| 12. In a vapour compression refrigeration system, the sub-cooling of refrigerant in the condenser results in: (a) Decrease in COP of the system (b) Decrease in the size of the condenser (c) Increase in the size of the evaporator (d) Increase in the size of the compressor |
| Ans. (c) |
| 13. In a vapour compression cycle, the refrigerant before entering the expansion device is a _____ (a) wet vapour at low pressure (b) wet vapour at high pressure (c) high pressure saturated liquid (d) low pressure saturated liquid |
| Ans. (c) |
| 14. A house requires 60 M cal/hr in winter for heating. Heat pump absorbs heat from cold air outside and requires 8 M cal/hr of work. The COP will be: (a) 0.75 (b) 6.5 (c) 7.5 (d) 15 |
COP= 7.5 |
| 15. A refrigerator based on reverse Carnot cycle works between two such temperatures that ratio between low and high temperature is 0.8. What is COP? (a) 2 (b) 3 (c) 4 (d) 5 |
| Ans. (c) |
| 16. A refrigeration system works on (a) second law of thermodynamics (b) first law of thermodynamics (c) zeroth law of thermodynamics (d) None of these |
| Ans : (a) |
| 17. According to Clausis statement : (a) Heat flows from hot substance to cold substance (b) Heat flows from hot substance to cold substance (c) Heat flows from cold substance to hot substance with aid of external work (d) b & c above
|
| 18. Tonnes of refrigeration mean____ (a) the weight of the machine is one tonne. (b) the weight of the refrigerant is one tonne. (c) the rate of the heat extraction is one tonne. (d) None of these |
| Ans : (c) |
| 19. If the COP of carnot refrigerator is 4, then the thermal efficiency of the Carnot engine would be_____ |
(c) 0.2 (d) 0.18
Ans : (b)
|
| (a) 1.2 (b) 1.26 (c) 1.3 (d) 2 |
| Ans. (c) |