Practice Test: Question Set - 15
1. The formation of frost on cooling coils in a refrigerator
- (A) Increases
heat transfer
- (B) Improves
C.O.P. of the system
- (C) Increases
power consumption
- (D) Reduces
power consumption
2. The power per tonne of refrigeration is
- (A) 3.5/C.O.P.
- (B) C.O.P/3.5
- (C) 3.5 × C.O.P.
- (D) None of
these
3. The wet bulb temperature during sensible heating of air
- (A) Remains
constant
- (B) Increases
- (C) Decreases
- (D) None
of these
4. The relative humidity is defined as
- (A) The mass of
water vapour present in 1 m3 of dry air
- (B) The mass of
water vapour present in 1 kg of dry air
- (C) 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
- (D) 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
5. As relative humidity decreases, the dew point temperature will be ________ wet bulb temperature.
- (A) Same
as
- (B) Lower
than
- (C) Higher
than
- (D) None
of these
6. In a psychrometric process, the sensible heat added is 30 kJ/s and the latent heat added is 20 kJ/s. The sensible heat factor for the process will be
- (A) 0.3
- (B) 0.6
- (C) 0.67
- (D) 1.5
7. An Electrolux refrigerator is called a _________ absorption system.
- (A) Single
fluid
- (B) Two
fluids
- (C) Three
fluids
- (D) None
of these
8. It is desired to condition the outside air from 70% relative humidity and 45° C dry bulb temperature to 50% relative humidity and 25° C dry bulb temperature (room condition). The practical arrangement will be
- (A) Dehumidification
- (B) Cooling and
humidification
- (C) Cooling
and dehumidification
- (D) Dehumidification
and pure sensible cooling
9. The difference between dry bulb temperature and wet bulb temperature, is called
- (A) Dry
bulb depression
- (B) Wet
bulb depression
- (C) Dew
point depression
- (D) Degree
of saturation
10. The coefficient of performance of Heat Pump is always _________ one.
- (A) Equal
to
- (B) Less
than
- (C) Greater
than
- (D) None
of these
11. An evaporator is also known as
- (A) Freezing
coil
- (B) Cooling
coil
- (C) Chilling
coil
- (D) All
of these
12. A refrigeration system
- (A) Removes
heat from a low temperature body and delivers it to a high temperature body
- (B) Removes
heat from a high temperature body and delivers it to a low temperature body
- (C) Rejects
energy to a low temperature body
- (D) None
of the above
13. Nusselt number (NN) is given by
- (A) NN
= hl/k
- (B) NN
= μ cp/k
- (C) NN
= ρ V l /μ
- (D) NN
= V²/t.cp
14. The temperature of ammonia after compression in a vapour compression system is
- (A) 20 to 50°C
- (B) 50 to 70°C
- (C) 70 to 110°C
- (D) None
of these
15. A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be
- (A) Lack
of cooling water
- (B) Water
temperature being high
- (C) Dirty
condenser surface
- (D) All
of these
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