Heat Transfer, Refrigeration and Air Conditioning problems
- 1. When the temperature of the surrounding is higher than the temperature of the body, then the heat loss by convection from the body to the surrounding will be
Options- A. positive
- B. negative
- C. zero
- D. none of these Discuss
Correct Answer: negative
- 2. The refrigerant supplied to a compressor must be
Options- A. superheated vapour refrigerant
- B. dry saturated liquid refrigerant
- C. a mixture of liquid and vapour refrigerant
- D. none of these Discuss
Correct Answer: superheated vapour refrigerant
- 3. According to Stefan's law, the total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature.
Options- A. Correct
- B. Incorrect Discuss
Correct Answer: Correct
- 4. During sensible heating of air, specific humidity remains constant.
Options- A. Agree
- B. Disagree Discuss
Correct Answer: Agree
- 5. Air refrigeration cycle is used in
Options- A. commercial refrigerators
- B. domestic refrigerators
- C. air-conditioning
- D. gas liquefaction Discuss
Correct Answer: gas liquefaction
- 6. In electrolux refrigerator
Options- A. ammonia is absorbed in hydrogen
- B. ammonia is absorbed in water
- C. ammonia evaporates in hydrogen
- D. hydrogen evaporates in ammonia Discuss
Correct Answer: ammonia evaporates in hydrogen
- 7. The wet bulb depression is zero when relative humidity is
Options- A. zero
- B. 0.5
- C. 0.75
- D. 1.0 Discuss
Correct Answer: 1.0
- 8. Which of the following statement is correct?
Options- A. The constant enthalpy lines are also constant wet bulb temperature lines.
- B. The wet bulb and dry bulb temperature are equal at saturation condition.
- C. The wet bulb temperature is a measure of enthalpy of moist air.
- D. all of the above Discuss
Correct Answer: all of the above
- 9. A good refrigerant should have
Options- A. high latent heat of vaporisation and low freezing point
- B. high operating pressures and low freezing point
- C. high specific volume and high latent heat of vaporisation
- D. low C.O.P. and low freezing point Discuss
Correct Answer: high latent heat of vaporisation and low freezing point
- 10. Dew point temperature corresponds to the saturation temperature of vapour at its partial pressure.
Options- A. True
- B. False Discuss
Correct Answer: True
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