Heat Transfer, Refrigeration and Air Conditioning – Section 2

41. The sensible heat gain is due to the __________ difference between the fresh air and the air in space.

A. temperature
B. humidity

Correct Answer: A. temperature

42. During cooling and dehumidification, dry bulb temperature

A. remains constant
B. increases
C. decreases

Correct Answer: C. decreases

43. The coefficient of performance of Electrolux refrigerator is the ratio of

A. heat supplied by the gas burner to the heat absorbed by the evaporator
B. heat absorbed by the evaporator to the heat supplied by the gas burner
C. heat supplied by the gas burner minus the heat absorbed by the evaporator to the heat supplied by the gas burner
D. heat absorbed by the evaporator minus the heat supplied by the gas burner to the heat absorbed by the evaporator

Correct Answer: B. heat absorbed by the evaporator to the heat supplied by the gas burner

44. The sulfur sticks, in case of leakage of ammonia refrigerant, gives white smoke.

A. True
B. False

Correct Answer: A. True

45. During gas charging in an ammonia vapor compression system, the connection is made at the compressor outlet.

A. Agree
B. Disagree

Correct Answer: A. Agree

46. The conditioned air supplied to the room must have the capacity to take up

A. room sensible heat load only
B. room latent heat load only
C. both room sensible heat and latent heat loads
D. none of the above

Correct Answer: C. both room sensible heat and latent heat loads

47. The process of removing moisture from the air, without change in its dry bulb temperature, is called dehumidification.

A. Correct
B. Incorrect

Correct Answer: A. Correct

48. The specific humidity during dehumidification process

A. remains constant
B. increases
C. decreases

Correct Answer: C. decreases

49. Which of the following refrigerant has the lowest freezing point?

A. R-11
B. R-12
C. R-22
D. Ammonia

Correct Answer: C. R-22

50. For a white body, absorptivity (α ) = 0, reflectivity (ρ) = 1 and transmittivity (τ) = 0.

A. Correct
B. Incorrect

Correct Answer: A. Correct

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