REFRIGERATION and AIR CONDITIONING MCQ
50.In a spray washing system, if the temperature of water is higher than the dry bulb temperature of entering air, then the air is
A. Heated and dehumidified
B. Heated and humidified
C. Cooled and humidified
D. Cooled and dehumidified
51.In a refrigerating machine, heat rejected is _________ heat absorbed.
A. Equal to
B. Less than
C. Greater than
D. None of these
52.During sensible heating of air _________ decreases.
A. Wet bulb temperature
B. Relative humidity
C. Dry bulb temperature
D. Specific humidity
53.During humidification process, __________ increases.
A. Wet bulb temperature
B. Relative humidity
C. Dry bulb temperature
D. Specific humidity
54.The boiling point of ________ is 10.5°C.
A. Ammonia
B.R-12
C. Sulphur dioxide
D. Carbon dioxide
55.Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system
A. Strong solution to weak solution
B. Weak solution to strong solution
C. Strong solution to ammonia vapour
D. Ammonia vapours to weak solution
56.An infinite parallel planes with emissivities e₁ and e₂, the interchange factor for radiation from surface 1 to surface 2 is given by
A.(e₁ + e₂)/ e₁ + e₂ – e₁e₂
B.1/e₁ + 1/e₂
C. e₁ + e₂
D. e₁e₂
57.A one tonne refrigerating machine means that
A. One tonne is the total mass of machine
B. One tonne refrigerant is used
C. One tonne of water can be converted into ice
D. One tonne of ice when melts from and at 0° C in 24 hours, the refrigeration effect is equivalent to 210 kJ/min
58.When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be
A. Cooled and humidified
B. Cooled and dehumidified
C. Heated and humidified
D. Heated and dehumidified
59.The unit of thermal diffusivity is
A. m/hK
B. m/h
C.m²/h
D. m²/hK
60.Ammonia is
A. Non-toxic
B. Non-inflammable
C. Toxic and non-inflammable
D. Highly toxic and inflammable
