MCQ
2221. Vertical Laes on pressure-enthalpy chart show consent-
pressure lines
total heat lines
temperature lines
entropy lines
2222. Freon group of refrigerants is-
Inflammable
toxic
non-inflanzaable and toxic
non-toxic and non-inflammable
2223. The COP of a domestic refrigerator in comparison to domestic air conditioner will be--
same
less
more
unpredictable
2224. The COP of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant will-
increase
decrease
unpredictable
remain unaffected
2225. Most of the domestic refrigerators work on the following refrigeration system-.
vapour compression.
vapour absorption
Carnot cycle
electrolux refrigerator
2226. The evolution of heat of solution takes place in ammonia absorption plant when--
ammonia vapour goes into solution
ammonia vapour is driven out of solution
lithium bromide mixes with ammonia
weak solution mixes with strong solution
2227. The relative coefficient of performance is equal to-
Theortical COP/Actual COP
Actual COP/Theortical COP
Actual COP x Theoretical COP
none of these
2228. According to joule's law, the internal energy of a perfect gas is the funciton of absolute--
density
temperature
pressure
volume
2229. The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of COP-
more
equally
less
unpredictable
2230. In a refrigeration cycle, the flow of refrigerant is controlled by-
The basic functions of an expansion device used in refrigeration rystems are to:
1. Reduce pressure from condenser pressure to evaporator pressure, and
2. Regulate the refrigerant flow from the high-pres liquid line into the evaporator at a rate equal tot evaporation rate in the evaporate
Compressor
Condenser
Evaporator
Expansion valve
2231. Which of the following refrigerants has lowest freezing point?
Freon-12
NH
CO
Freon-22
2232. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is-.
same
less
more
unpredictable
2233. The coefficient of performance is the ratio of the refrigerant effect to the –
heat of compression
work done by compressor
enthalpy increase in compressor
all of the above
2234. The COP of a refrigeration cycle with increase in evaporatour temperature, keeping condenser temperature constant will-.
decrease
increase
remain unaffected
unpredictable
2235. Reducing suction pressure in refrigeration cycle-.
lowers evaporation temperature
increases power required per ton of refrigeration
lowers compressor capacity because vapour is highter
reduces weight displaced by piston
all of the above
2236. For the same capacity of plant, the COP of the vapor absorption refrigeration system is--
lower than the COP of the vapour compression refrigeration system
higher than the COP of the vapour compression refrigeration system
same as the COP of the vapour compression refrigeration system
none of the above
2237. Cooling water is required for following equipment in ammonia absorption plant-
condenser
evaporator
absorber
condenser, absorber and separator (rectifier)
2238. The mass of water vapour present in.......... is called absolute humidity.
1m³ of wet air
1kg of wet air
1m³ of dry air
1kg of dry air
2239. One tonne of refrigeration (1 TR) means that the heat removing capacity is-
21kJ/min
420kJ/min
210kJ/min
620kl/min
2240. The COP of a vapor compression plant in comparison to vapor absorption plant is-
more
same
less
unpredictable