271. Ram compression in turbojet involves____________________?
A. reduction of speed of incoming air and conversion of part of it into pressure energy
B. compression of inlet air
C. increasing speed of incoming air
D. lost work
E. leakage losses
272. A jet engine works on the principle of conservation of____________________?
D. linear momentum
E. angular momentum
273. Which of the following fuels can be used in turbojet engines _____________________?
A. liquid hydrogen
B. high speed diesel oil
D. demethylated spirit
E. methyl alcohol
274. A rocket engine for the combustion of its fuel_____________________?
A. carries its own oxygen
B. uses surrounding air
C. uses compressed atmospheric air
D. does not require oxygen
E. depends on electrical energy supplied by solar cells
275. Propulsive efficiency is defined as ratio of___________________?
A. thrust power and fuel energy
B. engine output and propulsive power
C. propulsive power and fuel input
D. thrust power and propulsive power
E. none of the above
276. In the cross compounding of the gas turbine plant__________________?
A. h.p. compressor L connected to h.p. turbine and l.p. compressor ot l.p. tur-bine
B. h.p. compressor is connected to l.p. turbine and l.p. compressor is con-nected to h.p. turbine
C. both the arrangements can be employed
D. all are connected in series
E. none of the above
277. A rocket works with maximum overall efficiency when air craft velocity is equal to the_________________?
A. jet velocity
B. twice the jet velocity
C. half the jet velocity
D. average of the jet velocity
E. no such co-relationship with jet velocity exists
278. The maximum propulsion efficiency of a turbojet is attained at around following speed __________________?
A. 550 km/hr
C. 1700 km/hr
D. 2400km /hr
E. 4000 km/hr
279. Propulsion efficiency of the following order-is obtained in practice _______________?
280. The air entry velocity m a rocket as compared to aircraft is_________________?
E. dependent on power and speed
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