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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

Correct Answer :

A. (v₁² -v₂²)/2g


Related Questions

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4

In a single stage, single acting reciprocating air compressor without clearance volume, the workdone is maximum during

A. Isothermal compression

B. Isentropic compression

C. Polytropic compression

D. None of these

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4

Ratio of compression is the ratio of

A. Gauge discharge pressure to the gauge intake pressure

B. Absolute discharge pressure to the absolute intake pressure

C. Pressures at discharge and suction corresponding to same temperature

D. Stroke volume and clearance volume

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4

A compressor at high altitudes will require ________ power.

A. Same

B. Less

C. More

D. None of these

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4

The degree of reaction of an axial flow turbine is the ratio of isentropic temperature drop in a blade row to the

A. Adiabatic temperature drop in the stage

B. Total temperature drop

C. Total temperature drop in the stage

D. Total adiabatic temperature drop

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4

Isothermal compression efficiency, even when running at high speed, can be approached by using

A. Multistage compression

B. Cold water spray

C. Both (A) and (B) above

D. Fully insulating the cylinder

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4

Producer gas is produced by

A. Carbonisation of coal

B. Passing steam over incandescent coke

C. Passing air and a large amount of steam over waste coal at about 65°C

D. Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast

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4

Reheating in multistage expansion gas turbine results in

A. High thermal efficiency

B. Reduction in compressor work

C. Decrease of heat loss in exhaust

D. Maximum work output

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4

The mass of gas turbine per kW developed is about ________ as that of an I.C. engine.

A. Same

B. One-half

C. One fourth

D. One sixth

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4

In a jet propulsion unit, the products of combustion after passing through the gas turbine are discharged into

A. Atmosphere

B. Vacuum

C. Discharge nozzle

D. Back to the compressor

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4

The fuel consumption in gas turbines is accounted for by

A. Lower heating value

B. Higher heating value

C. Heating value

D. Higher calorific value

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4

For minimum work required to compress and deliver a quantity of air by multistage compression

A. The compression ratio in each stage should be same

B. The intercooling should be perfect

C. The workdone in each stage should be same

D. All of the above

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4

The capacity of compressor will be highest when its intake temperature is

A. Lowest

B. Highest

C. Anything

D. Atmospheric

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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

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

The closed cycle in gas turbines

A. Provides greater flexibility

B. Provides lesser flexibility

C. In never used

D. Is used when gas is to be burnt

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4

Which of the following fuels can be used in turbojet engines?

A. Liquid hydrogen

B. High speed diesel oil

C. Kerosene

D. Methyl alcohol

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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

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4

Rotary compressors are suitable for

A. Large discharge at high pressure

B. Low discharge at high pressure

C. Large discharge at low pressure

D. Low discharge at low pressure

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4

1 m of air at atmospheric condition weighs approximately

A. 0.5 kg

B. 1.0 kg

C. 1.3 kg

D. 2.2 kg

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4

The efficiency of roots blower ________ with the increase in pressure ratio.

A. Decreases

B. Increases

C. Does not change

D. None of these

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4

The assumption made in two stage compression with intercooler is that

A. There is no pressure drop in the intercooler

B. The compression in both the cylinders is polytropic

C. The suction and delivery of air takes place at constant pressure

D. All of the above

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4

The overall efficiency of the compressed air system is the

A. Ratio of shaft output of the air motor to the shaft input to the compressor

B. Ratio of shaft input to the compressor to the shaft output of air motor

C. Product of shaft output of air motor and shaft input to the compressor

D. None of the above

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4

In a single acting reciprocating air compressor, without clearance, the compression of air may be

A. Isothermal

B. Polytropic

C. Isentropic

D. Any one of these

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4

Rotary compressor is best suited for

A. Large quantity of air at high pressure

B. Small quantity of air at high pressure

C. Small quantity of air at low pressure

D. Large quantity of air at low pressure

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4

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

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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

Compression efficiency is compared against

A. Ideal compression

B. Adiabatic compression

C. Isentropic compression

D. Isothermal compression

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4

In a closed cycle gas turbine, the air is compressed

A. Isothermally

B. Polytropically

C. Isentropically

D. None of these

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4

The weight per horse power ratio for gas in Turbine as compared to I.C. engine and steam turbine is

A. Same

B. Higher

C. Lower

D. None of these

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4

Euler's equation can be used for

A. Radial flow compressors

B. Axial flow compressors

C. Pumps

D. All of these