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What is the correct answer?

4

The critical pressure gives the velocity of steam at the throat

A. Equal to the velocity of sound

B. Less than the velocity of sound

C. More than the velocity of sound

D. None of these

Correct Answer :

A. Equal to the velocity of sound


Related Questions

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4

During storage, the heating value of coal

A. Increases

B. Decreases

C. Remain constant

D. May increase or decrease depending upon the method of storage

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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

100% efficiency of a thermal cycle cannot be achieved because of

A. Frictional losses

B. It is not possible to achieve 0°K temperature

C. Leakage

D. Non availability of ideal substance

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4

In designing air preheaters, the important design consideration is that

A. Approach temperature should be as low as possible

B. Handling and maintenance should be easier

C. Heat transfer area should be optimum

D. Stack gases should not be cooled to the dew point

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4

The purpose of governing in steam turbines is to

A. Maintain the speed of the turbine

B. Reduce the effective heat drop

C. Reheat the steam and improve its quality

D. Completely balance against end thrust

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4

Which of the following gases has the highest calorific value?

A. Producer gas

B. Coal gas

C. Water gas

D. Blast furnace gas

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4

Pick up the correct statement as regards Cornish boiler and Lancashire boiler

A. Cornish is fire tube and Lancashire is water tube

B. Cornish is water tube and Lancashire is fire tube

C. Cornish has two fire tubes and Lancashire has one

D. Lancashire has two fire tubes and Cornish has one

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4

The factor of evaporation for all boilers is always

A. Equal to unity

B. Less than unity

C. Greater than unity

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 fire tubes in a Locomotive boiler has _________ diameter.

A. 4.75 mm

B. 5.47 mm

C. 7.45 mm

D. 47.5 mm

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4

The pressure of steam in the engine cylinder at the beginning of the stroke is ________ the boiler pressure.

A. Equal to

B. Less than

C. Higher than

D. None of these

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4

The cylindrical shell of a Lancashire boiler has diameter from

A. 1 to 2 m

B. 1.25 to 2.25 m

C. 1.5 to 2.5 m

D. 1.75 to 2.75 m

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4

Pulverised fuel is used for

A. Better burning

B. More calorific value

C. Less radiation loss

D. Medium sized units

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4

A condenser in a steam power plant

A. Increases expansion ratio of steam

B. Reduces back pressure of steam

C. Reduces temperature of exhaust steam

D. All of these

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4

When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be

A. Choked

B. Under-damping

C. Over-damping

D. None of these

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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

In an impulse turbine, steam expands

A. Wholly in blades

B. Wholly in nozzle

C. Partly in the nozzle and partly in blades

D. None of these

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4

In which of the following boilers, the draught in furnace is increased by utilising exhaust steam from engine

A. Lancashire boiler

B. Locomotive boiler

C. Babcock and Wilcox boiler

D. Benson boiler

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4

The ratio of the actual vacuum to the ideal vacuum in a condenser is called

A. Condenser efficiency

B. Vacuum efficiency

C. Nozzle efficiency

D. Boiler efficiency

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4

The maximum discharge through a chimney occurs when the height of chimney is

A. Infinitely long

B. Around 200 meters

C. Equal to the height of the hot gas column producing draught

D. Outside temperature is very low

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4

Which of the following statement is correct for steam turbines as compared to reciprocating steam engines?

A. A steam turbine develops higher speeds

B. The efficiency of steam turbine is higher

C. The steam consumption is less

D. All of these

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4

The rate of steam produced in Benson boiler is

A. 100 tonnes/h

B. 135 tonnes/h

C. 175 tonnes/h

D. 250 tonnes/h

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4

For a Parson's reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then

A. α₁ = α₂ and β₁ = β₂

B. α₁ = β₁ and α₂= β₂

C. α₁ < β₁ and α₂ > β₂

D. α₁ = β₂ and β₁ = α₂

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4

The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called

A. Condenser efficiency

B. Vacuum efficiency

C. Nozzle efficiency

D. Boiler efficiency

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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

Boiler stays are used to

A. Prevent flat surfaces under pressure from tearing apart

B. Take care of failure in shear

C. Take care of failure in compression

D. Provide support for boiler

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4

The cylinder condensation or missing quantity may be reduced by

A. The efficient steam jacketing of the cylinder walls

B. Superheating the steam supplied to the engine cylinder

C. Keeping the expansion ratio small in each cylinder

D. All of the above

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4

Bomb calorimeter is used to determine

A. Higher calorific value at constant volume

B. Lower calorific value at constant volume

C. Higher calorific value at constant pressure

D. Lower calorific value at constant pressure

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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

A fusible plug is fitted in small boilers in order to

A. Avoid excessive build up of pressure

B. Avoid explosion

C. Extinguish fire if water level in the boiler falls below alarming limit

D. Control steam dome