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4

O₂ content in atmospheric air on weight basis is

A. 21 %

B. 23 %

C. 30 %

D. 40 %

Correct Answer :

B. 23 %


Related Questions

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4

An air preheater is installed

A. Before the economiser

B. Before the superheater

C. Between the economiser and chimney

D. None of these

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4

The value of diagram factor depends upon

A. Initial conditions of steam

B. Back pressure

C. Initial pressure of steam

D. All of these

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4

The equivalent evaporation is defined as

A. The ratio of heat actually used in producing the steam to the heat liberated in the furnace

B. The amount of water evaporated or steam produced in kg per kg of fuel burnt

C. The amount of water evaporated from and at 100°C into dry and saturated steam

D. The evaporation of 15.653 kg of water per hour from and at 100°C

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4

The water tubes in a Babcock and Wilcox boiler are

A. Horizontal

B. Vertical

C. Inclined

D. Horizontal and inclined

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4

Blow off cock in a boiler is used to

A. Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required

B. Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler

C. Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit

D. Increase the temperature of saturated steam without raising its pressure

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4

Stoichiometric quantity of air is the

A. Air present in atmosphere at NTP conditions

B. Air required for complete combustion of fuel with no excess air

C. Air required for optimum combustion so as to have reasonable excess air

D. Air required to convert CO into CO₂

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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 missing quantity per stroke is equal to

A. Cylinder feed indicated mass of steam

B. Cylinder feed + indicated mass of steam

C. Mass of cushion steam + indicated mass of steam

D. Mass of cushion steam + cylinder feed

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4

The efficiency of the plant __________ with the mechanical draught.

A. Increases

B. Decreases

C. Remains constant

D. None of these

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4

A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as

A. Blow off cock

B. Fusible plug

C. Superheater

D. Stop valve

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4

A turbine is said to have an axial discharge when the steam leaves the blade tip at _________ to the direction of the blade motion.

A. 60°

B. 90°

C. 180°

D. 270°

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4

Which of the following statement is wrong?

A. The mechanical draught reduces the height of chimney.

B. The natural draught reduces the fuel consumption.

C. A balanced draught is a combination of induced and forced draught.

D. All of the above

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4

The pressure of feed water has to be raised before its entry into the boiler. The pressure is raised by a device known as

A. Feed pump

B. Injector

C. Feed check valve

D. Pressure gauge

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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

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4

The diameter of internal flue tubes of a Lancashire boiler is about _________ that of its shell.

A. One-fourth

B. One-third

C. Two-fifth

D. One-half

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4

An ideal regenerative cycle is

A. Equal to Carnot cycle

B. Less than Carnot cycle

C. More than Carnot cycle

D. Could be anything

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4

The ultimate analysis of fuel lists

A. Various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as percents by volume

B. Various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as percents by weight

C. Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

D. Fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

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4

An economiser is installed in a boiler primarily to

A. Superheat the steam

B. Reduce fuel consumption

C. Increase steam pressure

D. All of these

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4

The maximum discharge of steam through a convergent-divergent nozzle depends upon

A. Area of nozzle at throat

B. Initial pressure and volume of steam

C. Final pressure of steam leaving the nozzle

D. Both (A) and (B)

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4

A compound steam engine in which piston rods of high pressure and low pressure cylinders ' are attached to two different cranks set at 180° to each other, is called

A. Receiver type compound engine

B. Tandem type compound engine

C. Woolf type compound engine

D. Both (A) and (B)

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4

In a single acting steam engine

A. The steam is admitted on one side of the piston and one working stroke is produced during each revolution of the crankshaft

B. The steam is admitted, in turn, on both sides of the piston and one working stroke is produced during each revolution of the crankshaft

C. The steam is admitted on one side of the piston and two working strokes are produced during each revolution of the crankshaft

D. The steam is admitted, in turn, on both sides of the piston and two working strokes are produced during each revolution of the crankshaft

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4

In a steam engine, superheated steam from the boiler is fed into the steam chest at a pressure of

A. 10 atmospheres

B. 20 atmospheres

C. 30 atmospheres

D. 40 atmospheres

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4

An impulse turbine as compared to a reaction turbine, for a given power has _________ row of blades.

A. Equal

B. Less

C. More

D. None of these

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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

The critical pressure ratio for initially dry saturated steam is

A. 0.546

B. 0.577

C. 0.582

D. 0.601

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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

The shell of the Cochran boiler is made hemispherical

A. To give maximum space and strength

B. To withstand the pressure of steam inside the boiler

C. Both (A) and (B)

D. None of the above

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4

The diameter of a cylindrical shell of a Scotch marine boiler varies from

A. 1.5 to 2 m

B. 2.5 to 3.5 m

C. 3.5 to 4.5 m

D. None of these

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4

De-Laval turbine is a

A. Single rotor impulse turbine

B. Multi-rotor impulse turbine

C. Impulse reaction turbine

D. None of these

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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