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4

In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 mts. and the mass of steam passed out in same time was 4.8 kg. Dryness fraction is

A. 40 %

B. 25 %

C. 50 %

D. 80 %

Correct Answer :

D. 80 %


Related Questions

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4

Which of the following are boiler accessories?

A. Economiser

B. Superheater

C. Both (A) and (B)

D. None of these

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4

The critical pressure at which latent heat of vaporisation is zero is

A. 225.65 kgf/ cm²

B. 273 kgf/ cm²

C. 100 kgf/ cm²

D. 1 kgf/ cm²

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4

The amount of water evaporated from feed water at _________ into dry and saturated steam at 100° C at normal atmospheric pressure is called equivalent evaporation from and at 100° C.

A. 0°C

B. 40°C

C. 60°C

D. 100°C

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4

Water boils when its vapour pressure

A. Equals that of the surroundings

B. Equals 760 mm of mercury

C. Equals to atmospheric pressure

D. Equals the pressure of water in the container

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4

Water and sediment in fuel oil can be removed by

A. Heating the oil in the settling tanks

B. Cooling the oil in the settling tanks

C. Burning the oil

D. Suspension

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4

The rate of discharge through the nozzle __________ when the exit pressure is gradually reduced.

A. Remains same

B. Decreases

C. Increases

D. None of these

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4

The critical pressure ratio (p₂/p₁) is given by

A. (p₂/p₁) = [2/(n - 1)] n/(n + 1)

B. (p₂/p₁) = [2/(n + 1)] n/(n-1)

C. (p₂/p₁) = [(n - 1)/2] n + (1/n)

D. (p₂/p₁) = [(n + 1)/2] n - (1/n)

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4

The numbers of fire tubes in a Cochran boiler are

A. 75

B. 115

C. 165

D. 225

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4

The efficiency of reaction turbine is maximum when (where α = Angle made by the absolute velocity V at inlet)

A. Vb = 0.5 V cosα

B. Vb = V cos α

C. Vb = 0.5 V² cosα

D. Vb = V² cosα

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4

Expanding steam to a very low pressure (high vacuum) in steam engines is

A. Desirable

B. Economical

C. Essential

D. Uneconomical

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4

The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.

A. Same

B. Less

C. More

D. None of these

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4

In a De-Laval nozzle expanding superheated steam from 10 bar to 0.1 bar, the pressure at the minimum cross-section (i. e. pressure at throat, p₂) will be

A. 3.3 bar

B. 5.46 bar

C. 8.2 bar

D. 9.9 bar

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4

On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by

A. Horizontal straight line

B. Vertical straight line

C. Straight inclined line

D. Curved line

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4

Locomotive boiler is of the following type

A. Multi tubular

B. Horizontal

C. Internally fired

D. All of the above

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4

Which device is used in thermal power plants to reduce level of pollution?

A. Induced draft fan

B. Smoke meter

C. Chimney

D. Precipitator

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4

Which of the following boilers is best suited to meet fluctuating demands?

A. Babcock and Wilcox

B. Locomotive

C. Lancashire

D. Cochran

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4

A steam nozzle converts

A. Heat energy of steam into kinetic energy

B. Kinetic energy into heat energy of steam

C. Heat energy of steam into potential energy

D. Potential energy into heat energy of steam

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4

Fusible plug for boilers is made of fusible metal containing tin, lead, and

A. Bismuth

B. Copper

C. Aluminium

D. Nickel

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4

The safety valve at superheater as compared to drum safety valve setting is set at

A. Higher value

B. Lower value

C. Same value

D. Any value

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4

Which of the following statement is correct?

A. Lancashire boiler is a fire tube boiler.

B. Fire tube boilers are internally fired.

C. Babcock and Wilcox boiler is a water tube boiler.

D. All of the above

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4

Which of the following statement is correct?

A. The expansion of steam in a nozzle follows Rankine cycle.

B. The friction in the nozzle increases the dryness fraction of steam.

C. The pressure of steam at throat is called critical pressure.

D. All of the above

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4

The selection of type and size of a steam boiler depends upon

A. The power required and working pressure

B. The geographical position of the power house

C. The fuel and water available

D. All of the above

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4

The state of vapour under saturation condition is described by

A. Pressure alone

B. Temperature alone

C. Pressure and temperature

D. Pressure and dryness fraction

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4

The dry saturated steam at very low pressure, (510 kg/cm²) when throttled to atmosphere will become

A. Wet

B. Superheated

C. Remain dry saturated

D. Dry

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4

The steam leaves the nozzle at a

A. High pressure and a low velocity

B. High pressure and a high velocity

C. Low pressure and a low velocity

D. Low pressure and a high velocity

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4

The function of injector used in small capacity boilers is to

A. Create vacuum

B. Inject chemical solution in feed pump

C. Pump water, similar to boiler feed pump

D. Add make up water in the system

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4

With increase in load, radiant superheater has

A. Drooping characteristic

B. Linear characteristic

C. Rising characteristic

D. Flat characteristic

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4

Which of the following is a water tube boiler?

A. Locomotive boiler

B. Cochran boiler

C. Cornish boiler

D. Babcock and Wilcox boiler

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4

Gusset stays in a boiler are provided to

A. Prevent the bulging of flat surfaces

B. Avoid explosion in furnace

C. Prevent leakage of hot flue gases

D. Support furnace freely from top

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4

In a Woolf type compound engine, the high pressure and low pressure cylinders

A. Have common piston rod

B. Are set at 90°

C. Have separate piston rod

D. Are set in V-arrangement