Heat Transfer, Refrigeration and Air Conditioning problems
- 1. The ratio of heat extracted in the refrigerator to the workdone on the refrigerant is called
Options- A. coefficient of performance of refrigeration
- B. coefficient of performance of heat pump
- C. relative coefficient of performance
- D. refrigerating efficiency Discuss
Correct Answer: coefficient of performance of refrigeration
- 2. During dehumidification process, the relative humidity
Options- A. remains constant
- B. increases
- C. decreases Discuss
Correct Answer: decreases
- 3. The evaporator changes the low pressure liquid refrigerant from the expansion valve into
Options- A. high pressure liquid refrigerant
- B. low pressure liquid and vapour refrigerant
- C. low pressure vapour refrigerant
- D. none of these Discuss
Correct Answer: low pressure vapour refrigerant
- 4. When absorptivity (?) = 1, reflectivity (?) = 0 and transmittivity (?) = 0, then the body is said to be a
Options- A. black body
- B. grey body
- C. opaque body
- D. white body Discuss
Correct Answer: black body
- 5. The mass of water vapour present in __________ is called absolute humidity.
Options- A. 1 m3 of wetair
- B. 1 m3 of dry air
- C. 1 kg of wet air
- D. 1 kg of dry air Discuss
Correct Answer: 1 m3 of dry air
- 6. During sub-cooling, sensible heat from a liquid refrigerant is removed.
Options- A. Yes
- B. No Discuss
Correct Answer: Yes
- 7. The emissivity of a polished silver body is __________ as compared to black body.
Options- A. same
- B. low
- C. very low
- D. high Discuss
Correct Answer: very low
- 8. A grey body is one whose absorptivity does not vary with temperature and wave length of the incident ray.
Options- A. True
- B. False Discuss
Correct Answer: True
- 9. The wet bulb temperature during sensible cooling of air
Options- A. remains constant
- B. increases
- C. decreases Discuss
Correct Answer: decreases
- 10. The colour of the flame of halide torch, in case of leakage of freon refrigerant, will change to
Options- A. bright green
- B. yellow
- C. red
- D. orange Discuss
Correct Answer: bright green
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