Power Plant Engineering (2171910) MCQs

MCQs of Jet Propulsion

Showing 21 to 20 out of 30 Questions
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21.

Propulsive efficiency is defined as the 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
Answer:

Option (d)

22.

The efficiency of a jet engine is higher at

(a)

low speeds
(b)

high speeds
(c)

low altitudes
(d)

high altitudes
Answer:

Option (d)

23.

The propulsive power of the rocket is (where v₁ = Jet velocity, and v₂ = Aircraft velocity)

(a)

(v₁² -v₂²)/2g
(b)

(v₁ - v₂)²/2g
(c)

(v₁² -v₂²)/g
(d)

(v₁ - v₂)²/g
Answer:

Option (a)

24.

A turbo-prop is preferred to turbo-jet because

(a)

it has high propulsive efficiency at high speeds
(b)

it can fly at supersonic speeds
(c)

it can fly at high elevations
(d)

it has high power for take off
Answer:

Option (d)

25.

Turbofan engine employs

(a)

one air stream
(b)

two or more air streams
(c)

no air stream
(d)

solid fuel firing
Answer:

Option (b)

26.

In turbofan engine, the jet velocity as compared to turbojet engine is

(a)

less
(b)

more
(c)

same
(d)

may be less or more depending upon the speed
Answer:

Option (a)

27.

Only rocket engines can be propelled to space because

(a)

they can generate very high thrust
(b)

they have high propulsion efficiency
(c)

these engines can work on several fuels
(d)

they are not air-breathing engines
Answer:

Option (d)

28.

Which of the following statement is correct relating to rocket engines?

(a)

The combustion chamber in a rocket engine is directly analogous to the reservoir of a supersonic wind tunnel
(b)

The stagnation conditions exist at the combustion chamber
(c)

The exit velocities of exhaust gases are much higher than those in jet engine
(d)

all of these
Answer:

Option (d)

29.

A rocket engine uses __________ for the combustion of its fuel.

(a)

surrounding air
(b)

compressed atmospheric air
(c)

its own oxygen
(d)

none of these
Answer:

Option (c)

30.

A rocket works with maximum overall efficiency when aircraft velocity is equal to the

(a)

jet velocity
(b)

twice the jet velocity
(c)

half the jet velocity
(d)

average of the jet velocity
Answer:

Option (c)

Showing 21 to 20 out of 30 Questions
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