Mechanical Engineering MCQs

Option A: 6° to 20°

Option B: 220° to 345°

Option C: 65° to 220°

Option D: 15° to 120°

Correct Answer: 65° to 220° ✔

A. Paraffin
B. Gasoline
C. Heavy fuel oils
d) Patrol

Submitted by: Faheem Zaman Dhaunroo

Correct Answer: Heavy fuel oils ✔

Option A: steam turbines

Option B: water turbines

Option C: combustion turbines

Option D: Gas turbines

Correct Answer: water turbines ✔

Option A: Brown coal

Option B: Anthracite coal

Option C: Hard coke

Option D: Woodchar coal

Correct Answer: Hard coke ✔

Option A: Coke

Option B: Coal

Option C: Peat

Option D: None of these

Correct Answer: Coke ✔

Option A: Wood

Option B: Peat

Option C: Bituminous coal

Option D: Anthracite coal

Correct Answer: Anthracite coal ✔

Option A: 33500 kj/kg

Option B: 25000 kj/kg

Option C: 23000 kj/kg

Option D: 19700 kj/kg

Correct Answer: 19700 kj/kg ✔

Option A: Wood

Option B: Peat

Option C: Lignite

Option D: All of above

Correct Answer: All of above ✔

Option A: Higher

Option B: Lower

Option C: Equal

Option D: None of these

Correct Answer: Faheem Zaman Dhaunroo ✔

Option A: Constant temperature cycle

Option B: Constant Volume cycle

Option C: Constant Pressure Cycle

Option D: All of above

Correct Answer: Constant Pressure Cycle ✔

Option A: 90 lbf

Option B: 65.78 lbf

Option C: 0.00989 lbf

Option D: 3.00989 lbf

Correct Answer: 0.00989 lbf ✔

Option A: W between P and F

Option B: F between W and P

Option C: P between W and F

Option D: W, P and F all on one side

Correct Answer: P between W and F ✔

Option A: inductance

Option B: voltage

Option C: capacitance

Option D: None of these

Correct Answer: capacitance ✔

Option A: 1.013 bar

Option B: 760mm of Hg

Option C: 101.3KN/m2

Option D: All of these

Correct Answer: All of these ✔

Option A: Globe valve

Option B: Gate valve

Option C: Butterfly valve

Option D: Plug valve

Correct Answer: Globe valve ✔

Option A: throttle flow

Option B: check flow

Option C: change flow direction

Option D: start/stop flow

Correct Answer: start/stop flow ✔

Option A: Inside caliper

Option B: Dial indicator

Option C: Feeler gage

Option D: Measuring tape

Correct Answer: Inside caliper ✔

Option A: gap

Option B: hub

Option C: key

Option D: driver

Correct Answer: hub ✔

Option A: Breaking stress

Option B: Fracture stress

Option C: Yield point stress

Option D: Proof stress

Correct Answer: Breaking stress ✔

Option A: it has heating value

Option B: it helps in electrostatic precipitation of ash in flue-gases

Option C: it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low

Option D: it erodes furnace walls

Correct Answer: it erodes furnace walls ✔

Option A: inherent moisture and surface mois¬ture are different things

Option B: in some coals moisture may be present upto 40%

Option C: some moisture in coal helps in better burning which is not possible with completely dry coal

Option D: it increases thermal efficiency

Correct Answer: it increases thermal efficiency ✔

Option A: to provide proper conditions for con-tinuous complete combustion

Option B: mix fuel with air and ignite

Option C: separate ash from coal

Option D: maintain heat supply to prepare and ignite the incoming fuel

Correct Answer: separate ash from coal ✔

Option A: high burning rate is possible

Option B: heat release can be easily controlled

Option C: fuel burns economically

Option D: it is the best technique for burning high ash content fuel having low fusion ash

Correct Answer: it is the best technique for burning high ash content fuel having low fusion ash ✔

Option A: high calorific value

Option B: produce minimum smoke and gases

Option C: ease in storing

Option D: high ignition point

Correct Answer: high ignition point ✔

Option A: 15%

Option B: 20%

Option C: 30%

Option D: 45%

Correct Answer: 30% ✔

Option A: one-fourth

Option B: half

Option C: one

Option D: two

Correct Answer: one ✔

Option A: boiler efficiency, turhine efficiecny, generator efficiency

Option B: all the three above plus gas cycle efficiency

Option C: carnot cycle efficiency

Option D: regenerative cycle efficiency

Correct Answer: boiler efficiency, turhine efficiecny, generator efficiency ✔

Option 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

Option 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

Option C: feed pump is employed to supplement natural circulation in water wall type furnace

Option D: water is converted into steam in one pass without any recirculation

Correct Answer: water is converted into steam in one pass without any recirculation ✔

Option A: heat carried away by flue gases

Option B: heat carried away by ash

Option C: moisture present in fuel and steam formed by combustion of hydrogen in fuel

Option D: radiation

Correct Answer: all of the above ✔

Option A: lancashire boiler

Option B: locomotive boiler

Option C: babcock and wilcox boiler

Option D: cochran boiler

Correct Answer: locomotive boiler ✔

Option A: drooping characteristic

Option B: linear characterisstic

Option C: rising characteristic

Option D: flat characteristic

Correct Answer: rising characteristic ✔

Option A: from a metal wall from one medium to another

Option B: from heating an itermediate material and then heating the air from this material

Option C: by direct mixing ,

Option D: heat is transferred by bleeding some gases from furnace

Correct Answer: from a metal wall from one medium to another ✔

Option A: 100°C

Option B: above dew-point temperature of flue gases

Option C: below dew-point temperature of flue gases

Option D: less than wet bulb temperature of flue gases

Correct Answer: above dew-point temperature of flue gases ✔

Option A: approach temperature should be as low as possible

Option B: handling and maintenance should be easier

Option C: heat transfer area should be optimum

Option D: stack gases should not be cooled to the dew point

Correct Answer: stack gases should not be cooled to the dew point ✔

Option A: create vacuum

Option B: inject chemical solution in feed pump

Option C: pump water, similar to boiler feed pump

Option D: add make up water in the system

Correct Answer: pump water, similar to boiler feed pump ✔

Option A: the draft to be created

Option B: limitation of construction facilities

Option C: control of pollution

Option D: quantity of flue gases to be handled

Correct Answer: control of pollution ✔

Option A: more

Option B: equal

Option C: less

Option D: could be more or less depending on the size of plant

Correct Answer: less ✔

Option A: chimney

Option B: induced draft fan

Option C: both combined A. and B.

Option D: steam jet draught

Correct Answer: steam jet draught ✔

Option A: infinitely long

Option B: around 200 meters

Option C: equal to the height of the hot gas column producing draught

Option D: outside temperature is very low

Correct Answer: equal to the height of the hot gas column producing draught ✔

Option A: induced draft fan

Option B: smoke meter

Option C: chimney

Option D: precipitator

Correct Answer: precipitator ✔

Option A: carbon, hydrogen, nitrogen, sulphur, moisture

Option B: fixed carbon, ash, volatile matter, moisture

Option C: higher calorific value

Option D: lower calorific value

Correct Answer: carbon, hydrogen, nitrogen, sulphur, moisture ✔

Option A: all the fuel burns instantaneously producing high energy release

Option B: fuel burns with less air

Option 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

Option D: explosion in furnace

Correct Answer: 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 ✔

Option A: increases steam pressure

Option B: increases steam flow

Option C: decreases fuel consumption

Option D: decreases steam pressure

Correct Answer: decreases fuel consumption ✔

Option A: has high heating value

Option B: retards electric precipitation

Option C: promotes complete combustion

Option D: has highly corrosive effect

Correct Answer: has highly corrosive effect ✔

Option A: prevent the bulging of flat surfaces

Option B: avoid explosion in furnace

Option C: prevent leakage of hot flue gases

Option D: support furnace freely from top

Correct Answer: prevent the bulging of flat surfaces ✔

Option A: lowest temperature at which oil will flow under set condition

Option B: storage temperature

Option C: temperature at which fuel is pumped through burners

Option D: temperature at which oil is transported

Correct Answer: lowest temperature at which oil will flow under set condition ✔

Option A: the content of sulphur

Option B: the content of ash and heating value

Option C: the proximate analysis

Option D: the exact analysis

Correct Answer: the proximate analysis ✔

Option A: causing clinkering and slagging

Option B: corroding air heaters

Option C: spontaneous combustion during coal storage

Option D: facilitating ash precipitation

Correct Answer: all of the above ✔

Option A: heated sufficiently

Option B: burnt in excess air

Option C: heated to its ignition point

Option D: burnt as powder

Correct Answer: heated to its ignition point ✔

Option A: various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume

Option B: various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight

Option C: fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

Option D: fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

Correct Answer: fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash ✔

Option A: same value

Option B: higher value

Option C: lower value

Option D: lower/higher depending on steam flow

Correct Answer: higher value ✔

Option A: temperature, time, and turbulance

Option B: total air, true fuel, and turbulance

Option C: thorough mixing, total air, and temperature

Option D: total air, time, and temperature

Correct Answer: temperature, time, and turbulance ✔

Option A: higher effectiveness of boiler

Option B: high calorific value coal being burnt

Option C: fouling of heat transfer surfaces

Option D: raising of steam temperature

Correct Answer: fouling of heat transfer surfaces ✔

Option A: same

Option B: more

Option C: less

Option D: less or more depending on size of boiler

Correct Answer: more ✔

Option A: reduce hardness and for removal of solids

Option B: increase efficiency-of thermal power plant

Option C: increase *heat transfer rate

Option D: increase steam parameters

Correct Answer: ✔

Option A: tonnes/hr. of steam

Option B: pressure of steam in kg/cm2

Option C: temperature of steam in °C

Option D: all of the above

Correct Answer: all of the above ✔

Option A: 200-400 kcal/kg

Option B: 800-1200 kcal/kg

Option C: 2000-4000 kcal/kg

Option D: 5000-8000 kcal/kg

Correct Answer: 2000-4000 kcal/kg ✔

Option A: dry

Option B: wet

Option C: saturated

Option D: supersaturated

Correct Answer: wet ✔

Option A: remain unaffected

Option B: improve C. worsen

Option C: may improve/worsen depending on size

Option D: unpredictable

Correct Answer: may improve/worsen depending on size ✔

Option A: supply of excess, air

Option B: supply of excess coal

Option C: burning CO and unburnts in upper zone of furnace by supplying more air

Option D: fuel bed firing

Correct Answer: burning CO and unburnts in upper zone of furnace by supplying more air ✔

Option A: cavitation of .boiler feed pumps

Option B: corrosion caused by oxygen

Option C: heat transfer coefficient

Option D: pH value of water

Correct Answer: corrosion caused by oxygen ✔

Option A: increases

Option B: decreases

Option C: remains unaffected

Option D: first increases and then decreases

Correct Answer: decreases ✔

Option A: increases

Option B: decreases

Option C: remains constant

Option D: may increase or decrease depending upon the method of storage

Correct Answer: decreases ✔

Option A: very low pressure

Option B: atmospheric pressures

Option C: medium pressures

Option D: very high pressures

Correct Answer: very high pressures ✔

Option A: more heating surface

Option B: less heating surface

Option C: equal heating surface

Option D: heating surface depends on other parameters

Correct Answer: more heating surface ✔

Option A: increases

Option B: decreases

Option C: remains unchanged

Option D: increases/decreases depending on steam temperature requirements

Correct Answer: decreases ✔

Option A: corrosion

Option B: scale

Option C: carryover

Option D: embrittlement

Correct Answer: all of the above ✔

Option A: regulate flow of boiler water

Option B: check level of water in boiler drum

Option C: recirculate unwanted feed water

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

Correct Answer: allow high pressure feed water to flow to drum and not allow reverse flow to take place ✔

Option A: convection

Option B: radiation

Option C: conduction

Option D: radiation and conducton

Correct Answer: radiation ✔

Option A: 1 kg/cm

Option B: 6 kg/cm

Option C: 17 kg/cm2

Option D: 100 kg/cm2

Correct Answer: 17 kg/cm2 ✔

Option A: increases

Option B: decreases

Option C: remains unaffected

Option D: first increases and then decreases

Correct Answer: decreases ✔

Option A: increases

Option B: decreases

Option C: remains unaffected

Option D: first increases and then decreases

Correct Answer: decreases ✔

Option A: 100 kg/cm2 and 540°C

Option B: 1 kg/cm2 and 100°C

Option C: 218 kg/cm2 abs and 373°C

Option D: 218 kg/cm2 abs and 540°C

Correct Answer: 218 kg/cm2 abs and 373°C ✔

Option A: unburnt carbon in ash

Option B: incomplete combustion

Option C: ash content

Option D: flue gases

Correct Answer: flue gases ✔

Option A: induced draft fan and chimney

Option B: induced draft fan and forced draft fan

Option C: forced draft fan and chimney

Option D: any one of the above

Correct Answer: induced draft fan and forced draft fan ✔

Option A: kg of steam produced

Option B: steam pressure produced

Option C: kg of fuel fired

Option D: kg of steam produced per kg of fuel fifed

Correct Answer: kg of steam produced ✔

Option A: better burning

Option B: more calorific value

Option C: less radiation loss

Option D: medium sized units

Correct Answer: better burning ✔

Option A: smoky chimney exit

Option B: excess air in flue gases

Option C: measuring carbon mono-oxide in flue gases

Option D: measuring temperature of flue gases at exit of furnace

Correct Answer: measuring carbon mono-oxide in flue gases ✔

Option A: (1- moisture content)

Option B: (1 + moisture content)

Option C: 1 + moisture content

Option D: 1 – moisture content

Correct Answer: (1- moisture content) ✔

Option A: provide air around burners for obtaining optimum combustion

Option B: transport and dry the coal

Option C: cool the scanners

Option D: supply air for ignitors

Correct Answer: convert CO (formed in lower zone of furnace) into C02 at higher zone ✔

Option A: various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume

Option B: various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight

Option C: fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

Option D: fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

Correct Answer: various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight ✔

Option A: form lumps or masses of coke

Option B: burn freely

Option C: show little or no fusing action

Option D: burn completely

Correct Answer: form lumps or masses of coke ✔

Option A: provide air around burners for obtaining optimum combustion

Option B: transport and dry the coal

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

Option D: air delivered by induced draft fan

Correct Answer: provide air around burners for obtaining optimum combustion ✔

Option A: heating the oil in the settling tanks

Option B: cooling the oil in the settling tanks

Option C: burning the oil

Option D: suspension

Correct Answer: heating the oil in the settling tanks ✔

Option A: keep the burner tips cool

Option B: aid in proper combustion

Option C: cause sputtering, possibly extinguish¬ing flame

Option D: clean the nozzles

Correct Answer: cause sputtering, possibly extinguish¬ing flame ✔

Option A: provide air around burners for obtaining optimum combustion

Option B: transport and dry the coal

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

Option D: air-delivered by forced draft fan

Correct Answer: transport and dry the coal ✔

Option A: 21%

Option B: 23%

Option C: 30%

Option D: 40%

Correct Answer: 21% ✔

Option A: increase thermal efficiency of boiler

Option B: economise on fuel

Option C: extract heat from the exhaust flue gases

Option D: increase flue gas temperature

Correct Answer: increase thermal efficiency of boiler ✔

Option A: correct fuel air ratio

Option B: proper ignition temperature

Option C: 02 to support combustion

Option D: all the three above

Correct Answer: all the three above ✔

Option A: Higher calorific value at constant volume

Option B: Lower calorific value at constant volume ,

Option C: Higher calorific value at constant pressure

Option D: Lower calorific value at constant pressure

Correct Answer: Higher calorific value at constant volume ✔

Option A: carbon, hydrogen, nitrogen, sulphur, moisture

Option B: fixed carbon, ash, volatile matter, moisture

Option C: higher calorific value

Option D: lower calorific value

Correct Answer: fixed carbon, ash, volatile matter, moisture ✔

Option A: entropy

Option B: enthaply

Option C: pressure

Option D: temperature

Correct Answer: temperature ✔

Option A: desirable

Option B: economical

Option C: essential

Option D: optional

Correct Answer: economical ✔

Option A: boiler drum

Option B: superheater tubes

Option C: economiser

Option D: a separate coil

Correct Answer: a separate coil ✔

Option A: higher value

Option B: lower value

Option C: same value

Option D: any value

Correct Answer: lower value ✔

Option A: more

Option B: less

Option C: equal

Option D: may be more or less depending on capacity of reheater

Correct Answer: less ✔

Option A: from a metal wall from one medium to another

Option B: from heating an intermediateanaterial and then heating the air from this material

Option C: by direct mixing

Option D: heat is transferred by bleeding some gas from furnace

Correct Answer: from heating an intermediateanaterial and then heating the air from this material ✔

Option A: water

Option B: dry steam

Option C: wet steam

Option D: super heated steam

Correct Answer: super heated steam ✔

Option A: 2 cm

Option B: 6 Cm ,

Option C: 8 cm

Option D: 12 cm

Correct Answer: 6 Cm , ✔

Option A: drooping characteristic

Option B: lihear characterisstic

Option C: rising characteristic

Option D: flat characteristic

Correct Answer: drooping characteristic ✔