mechanical engineering MCQs – Page 115

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 Review each marked answer and report any item that may be outdated or unclear.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

2281. The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation___________________?
0

A. 1.0%

B. 0.50%

C. 0.10%

D. 10%.

E. 5%

2282. An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes________________?
0

A. two isobaric, two adiabatic and one constant volume

B. one adiabatic, two isobaric, and one constant volume

C. two adiabatic, one isobaric and one constant volume

D. two adiabatic and two isobaric

E. one adiabatic, one isobaric and two constant volume

2283. The pressure ratio in gas turbines is of the order of__________________?
0

A. 12:01

B. 2:l

C. 9:01

D. 4:01

E. 61: 1

2284. A centrifugal compressor works on the principle of__________________?
0

A. combination of A. and D.

B. generating pressure directly

C. conversion of pressure energy into kinetic energy

D. conversion of kinetic energy into pressure energy

E. centripetal action

2285. The work done per unit mass of air in compression willbe least when n is equal to______________?
0

A. 1.3

B. 1

C. 1.5

D. 1.4

E. 1.2 ,

2286. More than one stage will be preferred for reciprocating compressor if the delivery pressure is more than____________________?
0

A. none of the above

B. 2 kg/cm2

C. 6 kg/cm2

D. 14.7 kg/cm2

E. 10 kg/cm2

2287. In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of__________________?
0

A. liquid hydrogen

B. vacuum

C. compressed air

D. oxygen alone

E. atmospheric air

2288. The compressor capacity with decrease in suction temperature_________________?
0

A. remains unaffected

B. increases

C. increases upto certain limit and then decreases

D. decreases

E. may increase or decrease depending on compressor capacity

2289. For supplying intermittent small quantity of air at high pressure, following compressor is best suited__________________?
0

A. reciprocating

B. axial

C. screw

D. centrifugal

E. turbo jet

2290. The volumetirc efficiency of a compressor is calculated on the basis of __________________?
0

A. volume of air inhaled at N.T.P. conditions

B. volume of air inhaled at working conditions

C. none of the above

D. volume at 0C and 1 kg/cm2

E. volume at 20C and 1 kg/cm2

2291. The compression ratio in a gas turbine is of the roder of____________________?
0

A. 5:01

B. 3.5 : 1

C. 12:01

D. 8 : 1

E. 20:01

2292. In the aircraft propellers __________________?
0

A. all of the above

B. its functioning does not depend on presence of air

C. none of the above

D. propulsive matter is ejected from within the propelled body

E. the propulsive matter is caused to flow around the propelled body

2293. For a compressor, least work will be done if the compression is________________ ?
0

A. none of the above

B. somewhere in between isentropic and isothermal

C. isentropic

D. polytropic

E. isothermal

2294. Fighter bombers use following type of engine __________________?
0

A. ram-jet ,

B. turbo-propeller

C. pulsojet

D. turbo-jet

E. rocket

2295. The advantage of multistage compression over single stage compression is ________________?
0

A. all of the above

B. moisture free air

C. lower power consumption per unit of air delivered

D. decreased discharge temperature

E. higher volumetric efficiency

2296. Volumetric efficiency of air compressors is of the order of________________?
0

A. 20-30%

B. 70-90%

C. 40-50%

D. 90-100%

E. 60-70%

2297. During base load operation, the best method of controlling compressor is ___________________?
0

A. variable speed

B. relief valve

C. none of the above

D. start-stop motor

E. constant speed unloader

2298. It is not possible to use closed gas turbine cycle in aeronautical engines because_________________ ?
0

A. non of theses

B. it is inefficient

C. it is bulky

D. it requires cooling water for its operation

2299. The air entry velocity m a rocket as compared to aircraft is_________________?
0

A. more

B. zero

C. same

D. dependent on power and speed

E. less

2300. Water is injected in gas turbine cycle to___________________?
0

A. it is never done

B. control fire hazards

C. control temperature

D. increase efficiency

E. control output of turbine

Previous Next

Showing 2281 to 2300 of 4266 mcqs