MECHANICAL ENGINEERING (STEAM BOILERS, ENGINES, NOZZLES & TURBINES) MCQs

The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is

less

equal

may be less or more depending on temperature

unpredictable

Correct! Wrong!

Carbonation of coal is the process of

pulverising coal in inert atmosphere

heating wood in a limited supply of air at temperatures below 300°C

strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel

binding the pulverised coal into brick-ettes

enriching carbon in the coal

Correct! Wrong!

If partial pressure of air and steam be pa and ps respectively in a condenser, then according to Dalton’s law, the pressure in condenser is equal to

Ps-Pa

pa-ps

Pa+P

non of these

Correct! Wrong!

Heating of dry steam above saturation temperature is known as

enthalpy

superheating

supersaturation

latent heat

Correct! Wrong!

Superheating of steam is done at

constant volume

constant temperature

constant pressure

constant entropy

constant enthaply

Correct! Wrong!

The saturation temperature of steam with increase in pressure increases

linearly

rapidly first and then slowly

slowly first and then rapidly

inversely

none of the above

Correct! Wrong!

Coke is produced by

pulverising coal in inert atmosphere

heating wood in a limited supply of air at temperatures below 300GC

strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel

binding the pulverised coal into brick-etts

enriching carbon in the coal

Correct! Wrong!

The specific heat of superheated steam in kcal/kg is generally of the order of

0.1

0.3

0.5

0.8

Correct! Wrong!

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

horizontal straight line

vertical straight line

straight inclined line

curved line

none of the above

Correct! Wrong!

Hygrometery deals with the

Hygroscopic substances

water vapour in air

temperature of air

pressure of air

density measurement

Correct! Wrong!

Efficiency of rankine cycle can be increased by

decreasing initial steam pressure and temperature

increasing exhaust pressure

decreasing exhaust pressure

increasing the expansion ratio

increasing number of regenerative heaters

Correct! Wrong!

Lancashire boiler is of

stationary fire tube-type

horizontal type

natural cirulation type

internally fired type

all of the above

Correct! Wrong!

Which of the following substance will have same percentage in both proximate and ultimate analysis

ash

volatile matter

moisture

hydrogen

none of the above

Correct! Wrong!

The biggest size of thermal power unit operating in India is

30 MW

60 MW

100 MW

500 MW

Correct! Wrong!

The diameter of internal flue tubes in a Lancashire boiler compared to its shell is

one-half

one-third

one-fourth

one-fifth

two-fifth

Correct! Wrong!

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

babcock and wilcox

locomotive

lancashire

cochran

comish

Correct! Wrong!

The function of injector used in small steam plants is to

create vacuum in furnace

create vacuum at turbine exhaust

pump feed water

dose chemicals in feed water

control steam temperature by injecting water

Correct! Wrong!

The basic purpose of drum in boiler is to

serve as storage of steam

serve as storage of feed water for water wall

remove salts from water

separate steam from water

Correct! Wrong!

Which of the following is a water tube boiler

locomotive boiler

Cochran boiler

Cornish boiler

Babcock and Wilcox boiler

Lancashire boiler

Correct! Wrong!

The change in internal energy in steam engines equals to

work done during the rankine cycle

work done during compression

work done during adiabatic expansion

change in enthalpy

none of the above

Correct! Wrong!

An ideal regenerative cycle is

equal to carnot cycle

less than carnot cycle

more than carnot cycle

could be anything

none of the above

Correct! Wrong!

Adiabatic process is

essentially an isentropic process

non-heat transfer process

reversible process

constant temperature process

constant enthalpy process

Correct! Wrong!

The number of drums in Benson steam generator is

one

two

one steam drum and one water drum

no drum

none of the above

Correct! Wrong!

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

boiler effectiveness

boiler evaporative capacity

factor of evaporation

equivalent evaporation

boiler efficiency

Correct! Wrong!

In regenerative air preheater, the heat is transferred

from a metal wall from one medium to another

from heating an intermediate material and then heating the air from this material

by direct mixing

heat is transferred by bleeding some gas from furnace

none of the above

Correct! Wrong!

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

higher value

lower value

same value

any value

none of the above

Correct! Wrong!

Bomb calorimeter is used to determine

Higher calorific value at constant volume

Lower calorific value at constant volume

Higher calorific value at constant pressure

Lower calorific value at constant pressure

None of the above

Correct! Wrong!

Caking coals are those which

form lumps or masses of coke

burn freely

show little or no fusing action

burn completely

do not form ash

Correct! Wrong!

Tertiary air is the air used to

provide air around burners for obtaining optimum combustion

transport and dry the coal

cool the scanners

supply air for ignitors

convert CO (formed in lower zone of furnace) into C02 at higher zone

Correct! Wrong!

The feed check valve is used in order to

regulate flow of boiler water

check level of water in boiler drum

recirculate unwanted feed water

allow high pressure feed water to flow to drum and not allow reverse flow to take place

none of the above

Correct! Wrong!

Deaeration of feed water is carried out because it reduces

cavitation of boiler feed pumps

corrosion caused by oxygen

heat transfer coefficient

pH value of water

weight of water to be handled

Correct! Wrong!

Calorific value of coal is of the order of

200-400 kcal/kg

800-1200 kcal/kg

2000-4000 kcal/kg

5000-8000 kcal/kg

8000-10,000 kcal/kg

Correct! Wrong!

Green coal, in order to be burnt, must be

heated sufficiently

burnt in excess air

heated to its ignition point

burnt as powder

burnt as lumps

Correct! Wrong!

Pour point of fuel oil is the

lowest temperature at which oil will flow under set condition

storage temperature

temperature at which fuel is pumped through burners

temperature at which oil is transported

none of the above

Correct! Wrong!

An economiser in a boiler

increases steam pressure

increases steam flow

decreases fuel consumption

decreases steam pressure

increases life of boiler

Correct! Wrong!

Ultimate analysis of fuel is determination of percentage of

carbon, hydrogen, nitrogen, sulphur, moisture

fixed carbon, ash, volatile matter, moisture

higher calorific value

lower calorific value

best analysis

Correct! Wrong!

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

induced draft fan

smoke meter

chimney

precipitator

pulveriser

Correct! Wrong!

The height of chimney in a power plant is governed by

the draft to be created

limitation of construction facilities

control of pollution

quantity of flue gases to be handled

all of the above

Correct! Wrong!

With increase in load, convection superheater has

drooping characteristic

linear characterisstic

rising characteristic

flat characteristic

none of the above

Correct! Wrong!

Thermal efficiency of a thermal power plant is of the order of

15%

20%

30%

45%

60%

Correct! Wrong!

The overall efficiency of thermal power plant is

boiler efficiency, turhine efficiecny, generator efficiency

all the three above plus gas cycle efficiency

carnot cycle efficiency

regenerative cycle efficiency

rankine cycle efficiency

Correct! Wrong!

Which is not correct statement about the function of furnace

to provide proper conditions for con-tinuous complete combustion

mix fuel with air and ignite

separate ash from coal

maintain heat supply to prepare and ignite the incoming fuel

to minimise radiation losses

Correct! Wrong!

MECHANICAL ENGINEERING (STEAM BOILERS, ENGINES, NOZZLES & TURBINES) MCQs

The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is

Carbonation of coal is the process of

If partial pressure of air and steam be pa and ps respectively in a condenser, then according to Dalton’s law, the pressure in condenser is equal to

Heating of dry steam above saturation temperature is known as

Superheating of steam is done at

The saturation temperature of steam with increase in pressure increases

Coke is produced by

The specific heat of superheated steam in kcal/kg is generally of the order of

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

Hygrometery deals with the

Efficiency of rankine cycle can be increased by

Lancashire boiler is of

Which of the following substance will have same percentage in both proximate and ultimate analysis

The biggest size of thermal power unit operating in India is

The diameter of internal flue tubes in a Lancashire boiler compared to its shell is

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

The function of injector used in small steam plants is to

The basic purpose of drum in boiler is to

Which of the following is a water tube boiler

The change in internal energy in steam engines equals to

An ideal regenerative cycle is

Adiabatic process is

The number of drums in Benson steam generator is

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

In regenerative air preheater, the heat is transferred

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

Bomb calorimeter is used to determine

Caking coals are those which

Tertiary air is the air used to

The feed check valve is used in order to

Deaeration of feed water is carried out because it reduces

Calorific value of coal is of the order of

Green coal, in order to be burnt, must be

Pour point of fuel oil is the

An economiser in a boiler

Ultimate analysis of fuel is determination of percentage of

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

The height of chimney in a power plant is governed by

With increase in load, convection superheater has

Thermal efficiency of a thermal power plant is of the order of

The overall efficiency of thermal power plant is

Which is not correct statement about the function of furnace

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