MCQ
2221. The COP of a vapor compression plant in comparison to vapor absorption plant is-
more
same
less
unpredictable
2222. Which of the following refrigerants has lowest freezing point?
Freon-12
NH
CO
Freon-22
2223. Vertical Laes on pressure-enthalpy chart show consent-
pressure lines
total heat lines
temperature lines
entropy lines
2224. 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
2225. The COP of a domestic refrigerator in comparison to domestic air conditioner will be--
same
less
more
unpredictable
2226. The relative coefficient of performance is equal to-
Theortical COP/Actual COP
Actual COP/Theortical COP
Actual COP x Theoretical COP
none of these
2227. One tonne of refrigeration (1 TR) means that the heat removing capacity is-
21kJ/min
420kJ/min
210kJ/min
620kl/min
2228. Cooling water is required for following equipment in ammonia absorption plant-
condenser
evaporator
absorber
condenser, absorber and separator (rectifier)
2229. 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
2230. 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
2231. 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
2232. The COP of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant will-
increase
decrease
unpredictable
remain unaffected
2233. According to joule's law, the internal energy of a perfect gas is the funciton of absolute--
density
temperature
pressure
volume
2234. 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
2235. Most of the domestic refrigerators work on the following refrigeration system-.
vapour compression.
vapour absorption
Carnot cycle
electrolux refrigerator
2236. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is-.
same
less
more
unpredictable
2237. In a refrigeration cycle, the flow of refrigerant is controlled by-
Compressor
Condenser
Evaporator
Expansion valve
Himalay Sen Sir
মেকানিক্যাল ইঞ্জিনিয়ারিং MCQ
mechanical mcq
মেকানিক্যাল বিগত সালের প্রশ্ন সমাধান
রেফ্রিজারেশন mcq
ব্যাখ্যা: 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
2238. 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
2239. The COP of a refrigeration cycle with increase in evaporatour temperature, keeping condenser temperature constant will-.
decrease
increase
remain unaffected
unpredictable
2240. Freon group of refrigerants is-
Inflammable
toxic
non-inflanzaable and toxic
non-toxic and non-inflammable