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Current Affairs January 2024

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Which of the following coals has the highest calorific value?

A. Anthracite coal

B. Bituminous coal

C. Lignite

D. Peat

Correct Answer :

A. Anthracite coal


Related Questions

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Water tube boilers are those in which

A. Flue gases pass through tubes and water around it

B. Water passes through the tubes and flue gases around it

C. Work is done during adiabatic expansion

D. Change in enthalpy

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In a boiler, the heat is lost

A. To dry flue gases

B. In moisture present in the fuel

C. To steam formed by combustion of hydrogen per kg of fuel

D. All of the above

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A nozzle is said to be a divergent nozzle

A. When the cross-section of the nozzle increases continuously from entrance to exit

B. When the cross-section of the nozzle decreases continuously from entrance to exit

C. When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit

D. None of the above

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Besides mean effective pressure, the data required to determine the indicated power of an engine include

A. Piston diameter, length of stroke and calorific value of fuel

B. Piston diameter, specific fuel consumption and Calorific value of fuel

C. Piston diameter, length of stroke and speed of rotation

D. Specific fuel consumption, speed of rotation and torque

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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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The basic purpose of drum in boiler is to

A. Serve as storage of steam

B. Serve as storage of feed water for water wall

C. Remove salts from water

D. Separate steam from water

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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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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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The dry saturated steam at very high pressure (150200 kg/cm²) when throttled to atmosphere will become

A. Wet

B. Superheated

C. Remain dry saturated

D. Dry

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Alkaline pyrogallate is used in Orsat's apparatus for absorption of

A. CO₂

B. CO

C. O₂

D. N₂

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In forced recirculation type boiler,

A. Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum

B. Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam

C. Feed pump is employed to supplement natural circulation in water wall type furnace

D. Water is converted into steam in one pass without any recirculation

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The ratio of heat utilised to produce steam and the heat liberated in furnace is known as

A. Boiler effectiveness

B. Boiler evaporative capacity

C. Factor of evaporation

D. Boiler efficiency

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Which type of boiler can meet rapid changes of load?

A. Vertical fire tube type

B. Horizontal fire tube type

C. Horizontal water tube type

D. Forced circulation type

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O₂ content in atmospheric air on volume basis is

A. 21 %

B. 23 %

C. 30 %

D. 40 %

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The function of an eccentric rod is

A. To provide reciprocating motion to the slide valve

B. To convert reciprocating motion of the piston into rotary motion of the crank

C. To convert rotary motion of the crankshaft into to and fro motion of the valve rod

D. To provide simple harmonic motion to the D-slide valve

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Pour point of fuel oil is the

A. Lowest temperature at which oil will flow under set condition

B. Storage temperature

C. Temperature at which fuel is pumped through burners

D. Temperature at which oil is transported

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Spontaneous combustion is a phenomenon in which

A. All the fuel burns instantaneously producing high energy release

B. Fuel burns with less air

C. Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal

D. Explosion in furnace

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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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The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by

A. V = 2g H'

B. V = 2g/H'

C. V = H'/2g

D. V = 2gH'

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A single acting steam engine produces ________ power than that of double acting steam engine.

A. Equal

B. Half

C. Double

D. Four times

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The specific volume of steam with increase in pressure decreases

A. Linearly

B. Slowly first and then rapidly

C. Rapidly first and then slowly

D. Inversely

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The heat balance sheet for the boiler shows the

A. Complete account of heat supplied by 1 kg of dry fuel and the heat consumed

B. Moisture present in the fuel

C. Steam formed by combustion of hydrogen per kg of fuel

D. All of the above

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The temperature of flue gases at air heater outlet should be

A. 100°C

B. Above dew point temperature of flue gases

C. Below dew point temperature of flue gases

D. Less than wet bulb temperature of flue gases

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The radius of a dished head is taken approximately as

A. One fourth

B. Half

C. One

D. Two

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The diameter of Cornish boiler is of the order of

A. 12 m

B. 1.52.5 m

C. 23 m

D. 2.53.5 m

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Boiler H.P. is defined as the

A. Steam evaporation rate per kg of fuel fired

B. Work done in evaporating 1 kg of steam per hour from and at 100°C into dry saturated steam

C. The evaporation of 15.65 kg of water per hour from and at 100°C into dry saturated steam

D. Work done by 1 kg of steam at saturation condition

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Which of the following statement is wrong?

A. The critical pressure gives the velocity of steam at the throat equal to the velocity of sound.

B. The flow in the convergent portion of the nozzle is subsonic.

C. The flow in the divergent portion of the nozzle is supersonic.

D. To increase the velocity of steam above sonic velocity (supersonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary.

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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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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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Boiler parameters are expressed by

A. Tonnes/hr. of steam

B. Pressure of steam in kg/cm²

C. Temperature of steam in °C

D. All of the above