Practice Test: Question Set - 06
1. 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
2. The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is
- (A) Bigger
- (B) Smaller
- (C) Equal
- (D) Smaller/bigger
depending on capacity
3. The coefficient of performance (C.O.P.) of a refrigerator working as a heat pump is given by
- (A) (C.O.P.)P = (C.O.P.)R
+ 2
- (B) (C.O.P.)P = (C.O.P.)R
+ 1
- (C) (C.O.P)P = (C.O.P)R -
1
- (D) (C.O.P)P = (C.O.P)R
4. Presence of moisture in a refrigerant affects the working of
- (A) Compressor
- (B) Condenser
- (C) Evaporator
- (D) Expansion valve
5. During heating and humidification, the final relative humidity of air
- (A) Can be lower
or higher than that of the entering air
- (B) Is lower
than that of the entering air
- (C) Is higher
than that of the entering air
- (D) None of the
above
6. Which of the following cycles uses air as the refrigerant?
- (A) Ericson
- (B) Stirling
- (C) Carnot
- (D) Bell Coleman
7. The curved lines on a psychrometric chart indicates
- (A) Dry bulb
temperature
- (B) Wet
bulb temperature
- (C) Dew point
temperature
- (D) Relative
humidity
8. On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process
- (A) Involves no change in
volume
- (B) Takes place at
constant temperature
- (C) Takes place at
constant entropy
- (D) Takes place at
constant pressure
9. When the temperature of the surrounding is higher than the temperature of the body, then the heat loss by convection from the body to the surrounding will be
- (A) Positive
- (B) Negative
- (C) Zero
- (D) None
of these
10. The general rule for rating refrigeration systems (excepting for CO₂ system) is to approximate following h.p. per ton of refrigeration
- (A) 0.1 to 0.5 h.p. per ton of refrigeration
- (B) 0.5 to 0.8 h.p. per ton of refrigeration
- (C) 1 to 2 h.p. per ton of refrigeration
- (D) 2 to 5 h.p. per ton of refrigeration
11. The atmospheric air at dry bulb temperature of 15°C enters a heating coil maintained at 40°C. The air leaves the heating coil at 25°C. The bypass factor of the heating coil is
- (A) 0.376
- (B) 0.4
- (C) 0.6
- (D) 0.67
12. The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P.
- (A) More
- (B) Less
- (C) Equally
- (D) Unpredictable
13. Most thermostatic expansion valves are set for a superheat of
- (A) 5°C
- (B) 10°C
- (C) 15°C
- (D) 20°C
14. In a refrigeration system, heat absorbed in comparison to heat rejected is
- (A) More
- (B) Less
- (C) Same
- (D) More for small
capacity and less for high capacity
15. A thermostatic expansion valve in a refrigeration system
- (A) Ensures
the evaporator completely filled with refrigerant of the load
- (B) Is
suitable only for constant load systems
- (C) Maintains
different temperatures in evaporator in proportion to load
- (D) None
of the above
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