Heat Transfer, Refrigeration and Air Conditioning problems
- 1. In air-conditioning of aeroplanes, using air as a refrigerant, the cycle used is
Options- A. reversed Carnot cycle
- B. reversed Joule cycle
- C. reversed Brayton cycle
- D. reversed Otto cycle Discuss
Correct Answer: reversed Brayton cycle
- 2. The critical thickness of insulation for a sphere is
Options- A. k/h0
- B. 2k/h0
- C. h0/k
- D. h0/2k Discuss
Correct Answer: 2k/h0
- 3. The ratio of surface convection resistance to the internal conduction resistance is known as
Options- A. Grashoff number
- B. Biot number
- C. Stanton number
- D. Prandtl number Discuss
Correct Answer: Biot number
- 4. Wet bulb temperature is the temperature of air recorded by a thermometer, when
Options- A. it is not effected by the moisture present in the air
- B. its bulb is surrounded by a wet cloth exposed to the air
- C. the moisture present in it begins to condense
- D. none of the above Discuss
Correct Answer: its bulb is surrounded by a wet cloth exposed to the air
- 5. When there is an addition of water vapour to the air of enclosed space, a gain in __________ is said to occur.
Options- A. sensible heat
- B. latent heat Discuss
Correct Answer: latent heat
- 6. The temperature below which a gas is always liquified, is known as critical temperature.
Options- A. Correct
- B. Incorrect Discuss
Correct Answer: Incorrect
- 7. The expression
is used for calculating
Options- A. relative humidity
- B. humidity ratio
- C. degree of saturation
- D. pressure of water vapour Discuss
Correct Answer: humidity ratio
- 8. In aqua-ammonia absorption refrigeration system, incomplete rectification leads to accumulation of water in
Options- A. condenser
- B. evaporator
- C. absorber
- D. none of these Discuss
Correct Answer: condenser
- 9. In a black body, all radiations are rejected.
Options- A. True
- B. False Discuss
Correct Answer: False
- 10. An ordinary passenger aircraft requires a cooling system of capacity.
Options- A. 2 TR
- B. 4 TR
- C. 8 TR
- D. 10 TR Discuss
Correct Answer: 8 TR
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