mechanical engineering MCQs – Page 210

Practise multiple-choice questions from mechanical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

mechanical engineering Mcqs

1. compressors gas turbines and jet engines 2. theory of machines 3. nuclear power plants 4. engineering materials 5. strength of materials mechanical engineering 6. thermodynamics 7. heat transfer 8. i c engines 9. steam boilers engines nozzles and turbines 10. engineering mechanics 11. fluid mechanics mechanical engineering 12. production technology 13. machine design 14. hydraulic machines 15. workshop technology 16. refrigeration and air conditioning

4181. A refrigeration cycle operates between condenser temperature of + 27C and evaporator temperature of- 23C. The Cannot coefficient of performance of cycle will be_________________?
0

A. 6

B. 5

C. 0.2

D. 10

E. 1.2

4182. Critical temperature is the temperature above which _____________________?
0

A. none of the above

B. water will evaporate

C. a gas will immediately liquefy

D. water will never evaporate

E. a gas will never liquefy

4183. The COP of a domestic refrigerator___________________?
0

A. is equal to 1

B. depends upon the make

C. is less than 1

D. is more than 1

E. depends upon the weather conditions

4184. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is_________________?
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A. unpredictable

B. same

C. more or less depending on ambient conditions

D. more

E. less

4185. The evolution of heat of solution takes place in ammonia absorption plant when _____________________?
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A. lithium bromide is driven out of solution

B. lithium bromide mixes with ammonia

C. ammonia vapour goes into solution

D. ammonia vapour is driven out of solution

E. weak solution mixes with strong solution

4186. Vertical lines on pressure-enthalpy chart show constant_______________?
0

A. pressure lines

B. volume lines

C. total heat lines

D. temperature lines

E. entropy lines

4187. The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will______________________?
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A. increase

B. unpredictable

C. remain unaffected

D. may increase or decrease depending on the type of refrigerant used

E. decrease

4188. Clapeyron equation is applicable for registration at___________________?
0

A. saturation point of vapor

B. saturation point of liquid

C. critical point

D. sublimation temperature

E. triple point

4189. Presence of moisture in a refrigerant affects the working of___________________?
0

A. expansion valve

B. heat transfer

C. evaparator

D. compressor

E. condenser

4190. For obtaining high COP, the pressure range of compressor should be_______________?
0

A. low

B. high

C. any value

D. there is no such criterion

E. optimum

4191. In vapor compression cycle, the condition of refrigerant is very wet vapor________________?
0

A. before entering the expansion valve

B. after passing through the condenser

C. before entering the compressor

D. before passing through the condenser

E. after passing through the expansion or throttle valve

4192. The bank of tubes at the back of domestic refrigerator are _________________?
0

A. condenser tubes

B. refrigerant cooling tubes

C. capillary tubes

D. evaporator tubes

E. throttling device

4193. For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?
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A. perfectly tight vapour seal should be used

B. smaller cabinet should be used

C. refrigerant with high boiling point must be used

D. refrigerant with lower evaporation temperature should be used

E. bigger cabinet should be used

4194. Vapor compression refrigeration is some what like ____________________?
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A. Rankine cycle

B. reversed Camot cycle

C. none of the above

D. reversed Rankine cycle

E. Carnot cycle

4195. In vapor compression cycle, the condition of refrigerant is high pressure saturated liquid________________?
0

A. before entering the expansion valve

B. after passing through the condenser

C. before passing through the condenser

D. before entering the compressor

E. after passing through the expansion or thiottle valve

4196. In S.J. unit, one ton of refrigeration is equal to___________________?
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A. 210 kJ/min

B. 420 kJ/min

C. 840 kJ/min

D. 105 kJ/min

E. 21 kJ/min

4197. Condensing temperature in a refrigerator is the temperature_________________?
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A. at which refrigerant gas becomes liquid

B. of evaporator

C. of freezing zone

D. of cooling medium

E. condensing temperature of ice

4198. Ammonia-absorption refrigeration cycle requires__________________?
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A. none of the above

B. zero work input

C. maximum work input

D. very little work input

E. nearly same work input as for vapour compression cycle

4199. Which of the following cycles uses air as the refrigerant__________________?
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A. Bell-coleman

B. Carnot

C. Ericsson

D. Stirling

E. none of the above

4200. One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice_________________?
0

A. in 10 hours

B. in 1 minute

C. in 1 hour

D. in 24 hours

E. in 12 hours

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