Heat Transfer, Refrigeration and Air Conditioning MCQs
Heat Transfer, Refrigeration and Air Conditioning MCQs
These Heat Transfer, Refrigeration and Air Conditioning multiple-choice questions and their answers will help you strengthen your grip on the subject of Heat Transfer, Refrigeration and Air Conditioning. You can prepare for an upcoming exam or job interview with these Heat Transfer, Refrigeration and Air Conditioning MCQs.
So scroll down and start answering.
1: The optimum effective temperature for human comfort is
A. Same in winter and summer
B. Higher in winter than in summer
C. Lower in winter than in summer
D. Not dependent on season
2: The highest thermal diffusivity is of
A. Concrete
B. Iron
C. Lead
D. Wood
3: The temperature of ammonia after compression in a vapour compression system is
A. 50 to 70° C
B. None of these
C. 20 to 50° C
D. 70 to 110° C
4: The wet bulb temperature during sensible heating of air
A. Remains constant
B. Decreases
C. Increases
5: An electrolux refrigerator is called a __________ absorption system.
A. Single fluid
B. Two fluids
C. Three fluids
6: Degree of saturation or percentage humidity is
A. The mass of water vapour present in 1 m3 of dry air
B. The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
C. The mass of water vapour present in 1 kg of dry air
D. The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
7: In case of solids, the heat transfer takes place according to radiation.
A. Incorrect
B. Correct
8: The subcooling in a refrigeration cycle
A. Increases C.O.P.
B. None of these
C. Does not alter C.O.P.
D. Decreases C.O.P.
9: In a refrigerating machine, heat rejected is __________ heat absorbed.
A. Equal to
B. Greater than
C. Less than
10: The water, alcohol and ammonia have same refrigerating effect at different altitudes.
A. Yes
B. No
11: During sensible cooling of air __________ decreases.
A. Specific humidity
B. Wet bulb temperature
C. Dry bulb temperature
D. Relative humidity
12: 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)
A. Pb = pa/pv
B. Pb = pa + pv
C. Pb = pa - pv
D. Pb = pa x pv
13: In aqua-ammonia and Lithium-bromide water absorption refrigeration systems, the refrigerants are respectively
A. Ammonia and water
B. Water and lithium bromide
C. Water and water
D. Ammonia and lithium bromide
14: The centrifugal compressors are generally used for refrigerants that require
A. Small displacements and low condensing pressures
B. Large displacements and low condensing pressures
C. Small displacements and high condensing pressures
D. Large displacements and high condensing pressures
15: Thermal diffusivity is a
A. All of these
B. Physical property of a substance
C. Function of temperature
D. Dimensionless parameter
16: A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be
A. All of these
B. Lack of cooling water
C. Water temperature being high
D. Dirty condenser surface
17: The difference between dry bulb temperature and wet bulb temperature, is called
A. Wet bulb depression
B. Dew point depression
C. Degree of saturation
D. Dry bulb depression
18: The relative humidity is defined as
A. The mass of water vapour present in 1 kg of dry air
B. The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
C. The mass of water vapour present in 1 m3 of dry air
D. The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
19: During humidification process, __________ increases.
A. Specific humidity
B. Relative humidity
C. Wet bulb temperature
D. Dry bulb temperature
20: A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be
A. 2 KW
B. 3 kW
C. 1 kW
D. 4 kW
21: The process of ________ involves the movement or circulation of a mass or substance.
A. Convection
B. Conduction
C. Radiation
D. Reflection
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Heat Transfer, Refrigeration and Air Conditioning MCQs
