Heat Transfer, Refrigeration and Air Conditioning problems
- 1. In aqua-ammonia and Lithium-bromide water absorption refrigeration systems, the refrigerants are respectively
Options- A. water and water
- B. water and lithium bromide
- C. ammonia and lithium bromide
- D. ammonia and water Discuss
Correct Answer: ammonia and water
- 2. The total radiation from a black body per second per unit area is __________ fourth power of the absolute temperature. This statement is known as Stefan-Boltzmann law.
Options- A. equal to
- B. directly proportional to
- C. inversely proportional to Discuss
Correct Answer: directly proportional to
- 3. According to Dalton's law of partial pressures, (where pb = Barometric pressure, pa = Partial pressure of dry air, and pv = Partial pressure of water vapour)
Options- A. Pb = pa - pv
- B. Pb = pa + pv
- C. Pb = pa x pv
- D. Pb = pa/pv Discuss
Correct Answer: Pb = pa + pv
- 4. During a refrigeration cycle, heat is rejected by the refrigerant in a
Options- A. compressor
- B. condenser
- C. evaporator
- D. expansion valve Discuss
Correct Answer: condenser
- 5. The critical radius is the insulation radius at which the resistance to heat flow is
Options- A. maximum
- B. minimum
- C. zero
- D. none of these Discuss
Correct Answer: minimum
- 6. In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
Options- A. Reynold's number
- B. Grashoff's number
- C. Reynold's number, Grashoff's number
- D. Prandtl number, Grashoff's number Discuss
Correct Answer: Prandtl number, Grashoff's number
- 7. The humidity ratio or specific humidity is the mass of water vapour present in
Options- A. 1 m3 of wet air
- B. 1 m3 of dry air
- C. 1 kg of wet air
- D. 1 kg of dry air Discuss
Correct Answer: 1 kg of dry air
- 8. In case of solids, the heat transfer takes place according to radiation.
Options- A. Correct
- B. Incorrect Discuss
Correct Answer: Incorrect
- 9. Which of the following represents a heat pump?
Options- A.
- B.
- C.
- D.
Discuss
Correct Answer:
- 10. The condition of refrigerant after leaving the compressor and before entering the condenser is superheated vapour.
Options- A. Yes
- B. No Discuss
Correct Answer: Yes
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