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4

The compressed air may be used

A. In gas turbine plants

B. For operating pneumatic drills

C. In starting and supercharging of I.C. engines

D. All of the above

Correct Answer :

D. All of the above


Related Questions

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4

Water is injected in gas turbine cycle to

A. Control temperature

B. Control output of turbine

C. Control fire hazards

D. Increase efficiency

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4

High air-fuel ratio is used in gas turbines

A. To increase the output

B. To increase the efficiency

C. To save fuel

D. To reduce the exit temperature

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4

Ramjet engine

A. Is self operating at zero flight speed

B. Is not self operating at zero flight speed

C. Requires no air for its operation

D. Produces a jet consisting of plasma

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4

Isothermal compression efficiency can be attained by running the compressor

A. At very high speed

B. At very slow speed

C. At average speed

D. At zero speed

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4

Which is false statement about multistage compression?

A. Power consumption per unit of air delivered is low

B. Volumetric efficiency is high

C. It is best suited for compression ratios around 7:1

D. The moisture in air is condensed in the intercooler

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4

If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix I and o stand for entry and exit conditions, then in a rotary machine whose degree of reaction is unity

A. Vi = Vo

B. Vt > Vo

C. U < Vo

D. V = Uo

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4

The air entry velocity m a rocket as compared to aircraft is

A. Same

B. More

C. Less

D. Zero

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4

When air is to be compressed at a high pressure, then it is advantageous to use

A. Single stage compression

B. Multistage compression without intercooling

C. Multistage compression with intercooling

D. None of these

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4

In a centrifugal compressor, an increase in speed at a given pressure ratio causes

A. Increase in flow

B. Decrease in flow

C. Increase in efficiency

D. Increase in flow and decrease in efficiency

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4

If the clearance ratio for a reciprocating air compressor is 'K', then its volumetric efficiency is given by

A. 1 - k + k (p₁/p₂)1/n

B. 1 + k - k (p₂/p₁)1/n

C. 1 - k + k (p₁/p₂) n- 1/n

D. 1 + k - k (p₂/p₁) n-1/n

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4

If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches

A. Isothermal

B. Isentropic

C. Adiabatic

D. Isochoric

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4

Pick up the correct statement

A. Closed cycle gas turbine is an I.C engine

B. Gas turbine uses same working fluid over and over again

C. Ideal efficiency of closed cycle gas turbine plant is more than Carnot cycle efficiency

D. Thrust in turbojet is produced by nozzle exit gases.

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4

In the axial flow gas turbine, the work ratio is the ratio of

A. Compressor work and turbine work

B. Output and input

C. Actual total head temperature drop to the isentropic total head drop from total head inlet to static head outlet

D. Actual compressor work and theoretical compressor work

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4

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

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4

If p₁, is the pressure of air entering the L.P. cylinder and p₂ is the pressure of air leaving the L.P. cylinder (or intercooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D₁ = Dia. of L.P. cylinder, and D₂ = Dia. of H.P. cylinder)

A. D₁/D₂ = p₁ p₂

B. D₁/D₂ = p₁/p₂

C. D₁/D₂ = p₂/p₁

D. None of these

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4

The degree of reaction in an axial flow compressor is defined as the ratio of static enthalpy rise in the

A. Rotor to static enthalpy rise in the stator

B. Stator to static enthalpy rise in the rotor

C. Rotor to static enthalpy rise in the stage

D. Stator to static enthalpy rise in the stage

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4

The pressure of air at the beginning of the compression stroke is ________ the atmospheric pressure.

A. Equal to

B. Less than

C. More than

D. None of these

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4

Volumetric efficiency of a compressor without clearance volume

A. Increases with increase in compression ratio

B. Decreases with increase in compression ratio

C. Is not dependent upon compression ratio

D. May increase/decrease depending on compressor capacity

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4

For perfect intercooling in a two stage compressor

A. p₂/p₁ = p₃/p₂

B. p₁/p₃ = p₂/p₁

C. p₁ = p₃

D. p₁ = p₂ p₃

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4

In a compressor, free air delivered is the actual volume delivered at the stated pressure reduced to

A. N.T.P. conditions

B. Intake temperature and pressure conditions

C. 0°C and 1 kg/cm²

D. 20°C and 1 kg/cm²

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4

Euler's equation is applicable for

A. Centrifugal compressor

B. Axial compressor

C. Pumps

D. All of the above

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4

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

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4

For perfect intercooling in a three stage compressor

A. p₂/p₁ = p₃/p₂ = p₄/p₃

B. p₃/p₁ = p₄/p₂

C. p₁ p₂ = p₃ p₄

D. p₁ p₃ = p₂ p₄

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4

Stalling of blades in axial flow compressor is the phenomenon of

A. Air stream blocking the passage

B. Motion of air at sonic velocity

C. Unsteady periodic and reversed flow

D. Air stream not able to follow the blade contour

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4

The gas in cooling chamber of a closed cycle gas turbine is cooled at

A. Constant volume

B. Constant temperature

C. Constant pressure

D. None of these

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4

The stagnation pressure rise in a centrifugal compressor takes place

A. In the diffuser only

B. In the impeller only

C. In the diffuser and impeller

D. In the inlet guide vanes only

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4

The compressor efficiency is the

A. Isothermal H.P/indicated H.R

B. Isothermal H.P./shaft H.R

C. Total output/air input

D. Compression work/motor input

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4

Reheating in gas turbine results in

A. Increase of work ratio

B. Decrease of thermal efficiency

C. Decrease of work ratio

D. Both (A) and (B) above

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4

The pressure ratio for an open cycle gas turbine compared to closed cycle gas turbine of same h.p. is

A. Low

B. High

C. Same

D. Low/high depending on make and type

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4

Axial flow compressor has the following advantage over centrifugal compressor

A. Larger air handling ability per unit frontal area

B. Higher pressure ratio per stage

C. Aerofoil blades are used

D. Higher average velocities