260 Important Refrigeration And Air Conditioning MCQ Question and Answer | PDF Free Download
1.The boiling point of ammonia is
- A-10.5°C
- B-30°C
- C-33.3°C
- D-77.7°C
2.The formation of frost on cooling coils in a refrigerator
- AIncreases heat transfer
- BImproves C.O.P. of the system
- CIncreases power consumption
- DReduces power consumption
3.The bypass factor of a cooling coil decreases with
- ADecrease in fin spacing and increase in number of rows
- BIncrease in fin spacing and increase in number of rows
- CIncrease in fin spacing and decrease in number of rows
- DDecrease in fin spacing and decrease in number of rows
4.Air refrigerator works on
- AReversed Carnot cycle
- BBell Coleman cycle
- CBoth (A) and (B)
- DNone of these
5.Moisture should be removed from refrigerants to avoid
- AFreezing at the expansion valve
- BRestriction to refrigerant flow
- CCorrosion of steel plates
- DAll of these
6.A standard ice point temperature corresponds to the temperature of
- AWater at 0°C
- BIce at 4°C
- CSolid and dry ice
- DMixture of ice and water under equilibrium conditions
7.A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be
- A¼
- B1/3
- C3
- D4
8.The thermostatic expansion valve operates on the changes in the
- ADegree of superheat at exit from the evaporator
- BTemperature of the evaporator
- CPressure in the evaporator
- DNone of the above
9.The temperature of air recorded by a thermometer, when its bulb is surrounded by a wet cloth exposed to the air, is called
- AWet bulb temperature
- BDry bulb temperature
- CDew point temperature
- DNone of these
10.The temperature of air recorded by a thermometer, when it is not affected by the moisture present in the air, is called
- AWet bulb temperature
- BDry bulb temperature
- CDew point temperature
- DNone of these
11.The dry bulb temperature during sensible heating of air
- ARemains constant
- BIncreases
- CDecreases
- DNone of these
12.The wet bulb temperature during sensible cooling of air
- ARemains constant
- BIncreases
- CDecreases
- DNone of these
13.The relative humidity is defined as
- AThe mass of water vapour present in 1 m3 of dry air
- BThe mass of water vapour present in 1 kg of dry air
- CThe 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
- DThe 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
14.Moisture in Freon refrigeration system causes
- AIneffective refrigeration
- BHigh power consumption
- CFreezing automatic regulating valve
- DCorrosion of whole system
15.In case of sensible cooling of air, the coil efficiency is given by
- AB.P.F. – 1
- B1 - B.P.F.
- C1/ B.P.F.
- D1 + B.P.F.
16.The wet bulb depression indicates _________ humidity of the air.
- AAbsolute
- BRelative
- CSpecific
- DNone of these
17.Which of the following refrigerant is highly toxic and flammable?
- AAmmonia
- BCarbon dioxide
- CSulphur dioxide
- DR-12
18.The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy diagram represents
- ACondensation of the refrigerant vapour
- BEvaporation of the refrigerant liquid
- CCompression of the refrigerant vapour
- DMetering of the refrigerant liquid
19.The leakage in a refrigeration system using ammonia is detected by
- AHalide torch
- Bv
- CSoap and water
- DAll of these
20.The advantage of dry compression is that
- AIt permits higher speeds to be used
- BIt permits complete evaporation in the evaporator
- CIt results in high volumetric and mechanical efficiency
- DAll of the above