mechanical engineering MCQs – Page 161

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 Review each marked answer and report any item that may be outdated or unclear.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

3201. To reduce the possibility of knock in the C.I. engines, the first elements of fuel and air should have_______________?
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A. reactive mixture

B. high temperature

C. high density

D. short delay

E. all of the above

3202. A fuel will detonate less if it has___________________?
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A. proper self ignition temperature

B. lower self ignition temperature

C. none of the above

D. higher self ignition temperature

E. self ingition temperature has nothing to do with detonation

3203. A 5 BHP engine running at full load would consume diesel of the order of_________________?
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A. 0.3 kg/hr

B. 1 kg/hr

C. 3 kg/hr

D. 5 kg/hr

E. 10 kg/hr

3204. Flash point of fuel oil is __________________?
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A. temperature at which it catches fire without external aid

B. temperature at which it solidifies or congeals

C. minimum temperature to which1 oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

D. indicated by 90% distillation temperature, i.e. when 90% of sample oil has distilled off

E. none of the above

3205. Scavenging air in diesel engine means___________________?
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A. burnt air containing products of combustion

B. air used for forcing burnt gases out of engines cylinder during the exhaust period

C. forced air for cooling cylinder

D. air fuel mixture

E. air used for combustion sent under pres-sure

3206. Kerosene is distilled at________________?
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A. 350 450C

B. 30 65C

C. 220 350C

D. 450-550C

E. 65 220C

3207. Fuel consumption with increase in back pressure will________________?
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A. depend on other factors

B. increase

C. decrease

D. remain unaffected

E. none of the above

3208. Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following______________?
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A. ch of the following is false statement?

3209. The function of a distributor in an automobile is to__________________?
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A. regulate power

B. distribute charge, equally to all the cylinders

C. feed lub oil to all moving parts

D. inject fuel at appropriate time

E. time the spark

3210. In open combustion chamber in diesel engines____________________?
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A. fuel is injected into an auxiliary chamber that is separated from the cylinder by an orifice or throat

B. the shape and layout of the piston crown, the inlet port, and the valve produce the turbulent effect on fuel mixture

C. fuel is injected at atmospheric pressure

D. there are no valves.

E. only a part of air charge is contained in an auxiliary chamber in which the fuel starts to burn with insufficient air which due to explosion tendency mixes thoroughly into main cylinder charge

3211. It the temperature of intake air in IC engines is lowered, then its efficiency will_______________________?
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A. decrease upto certain limit and then in-crease

B. decrease

C. increase upto certain limit and then decrease

D. increase

E. remain same

3212. According to Recardos theory, detonation occurs due to______________________?
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A. none of the above

B. instantaneous auto-ignition of last part of charge to be burnt

C. improper mixing of air and fuel

D. self ignition temperature has nothing to do with detonation

E. improper combustion