Free Mechanical Engineering MCQs Mock Test Online with Answers

Q1 : In ordetjo obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will _________________?

A: remain unaffected B: improve C. worsen C: may improve/worsen depending on size D: unpredictable

Q2 : Size of boiler tubes is specified by___________________?

A: mean diameter and thickness B: inside diameter and thickness C: outside diameter and thickness D: outside diameter and inside diameter

Q3 : At critical point, i.e. p=225.65 kg/cm2, the latent enthalpy of vaporisation is______________?

A: maximum B: minimum C: zero D: depends on temperature also

Q4 : Overfire burning is the phenomenon of _____________________?

A: supply of excess, air B: supply of excess coal C: burning CO and unburnts in upper zone of furnace by supplying more air D: unpredictable

Q5 : Sulphur content of fuels is very important to the plant operators because it____________________?

A: has high heating value B: retards electric precipitation C: promotes complete combustion D: has highly corrosive effect

Q6 : A supercritical boiler is one that operates above the pressure and temperature of following values_____________________?

A: 100 kg/cm2 and 540°C B: 1 kg/cm2 and 100°C C: 218 kg/cm2 abs and 373°C D: 100 kg/cm2 abs and 373°C

Q7 : The normal stress in a fluid will be constant in all directions at a point only if__________________________?

A: it is incompressible B: it has uniform viscosity C: it has zero viscosity D: it is at rest

Q8 : For manometer, a better liquid combination is one having ___________________?

A: higher surface tension B: lower surface tension C: surface tension is no criterion D: high density and viscosity

Q9 : The steam temperature with increase in load in case of a boiler fitted with radiation super heater________________?

A: increases B: decreases C: remains unaffected D: first increases and then decreases

Q10 : Tertiary air is the air used to____________________?

A: provide air around burners for obtaining optimum combustion B: transport and dry the coal C: cool the scanners D: convert CO (formed in lower zone of furnace) into C02 at higher zone

Q11 : Free surface of a liquid tends to contract to the smallest possible area due to force of_______________?

A: surface tension B: viscosity C: friction D: cohesion

Q12 : Expanding steam to a very low pressure (high vacuum) in steam engines is _________________?

A: desirable B: economical C: optional D: uneconomical

Q13 : Practical fluids___________________?

A: are viscous B: . possess surface tension C: are compressible D: possess all the above properties

Q14 : In a throttling process_________________?

A: heat transfer takes place B: work is done by the expanding steam C: internal energy of steam changes D: none of the above

Q15 : The diameters of fire tubes and superheaer tubes in locomotive boiler are_________________?

A: 47.5 mm, 130 mm B: 32.5 mm, 180 mm C: 65.5 mm, 210 mm D: 24.5 mm, 65 mm

Q16 : Which is not correct statement about the function of furnace____________________?

A: to provide proper conditions for con-tinuous complete combustion B: mix fuel with air and ignite C: separate ash from coal D: maintain heat supply to prepare and ignite the incoming fuel

Q17 : 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

Q18 : Coke is produced by__________________?

A: pulverising coal in inert atmosphere B: heating wood in a limited supply of air at temperatures below 300GC C: strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel D: binding the pulverised coal into brick-etts

Q19 : The flow in which conditions do not change with time at any point, is known as_________________?

A: one dimensional flow B: uniform flow C: steady flow D: turbulent flow

Q20 : Which of the following solid fuel has high carbon content?

A: Coke B: Coal C: Peat D: None of these

Q21 : The shell diameter and length of locomotive boiler are_______________?

A: 1.5 m, 4 m B: 1 m, 4 m C: 1.5 m, 6 m D: 1.5 m, 8 m

Q22 : The latent heat of steam with increase of pressure__________________?

A: remains same B: increases C: decreases D: behaves unpredictably

Q23 : A body floats in stable equilibrium ____________________?

A: when its meatcentric height is zero B: when the metancentre is above e.g. C: when its e.g. is below it’s center of buoyancy D: metacentre has nothing to do with position of e.g. for determining stability

Q24 : The patrol is distilled at a temperature from :

A: 6° to 20° B: 220° to 345° C: 65° to 220° D: 15° to 120°

Q25 : 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

Q26 : Locomotive type’ boiler is__________________?

A: horizontal multitubular water tube boiler B: water wall enclosed furnace type C: vertical tubular fire tube type D: horizontal multi-tubular fire tube type

Q27 : The safety valve at superheater as compared to drum safety valve setting is set at___________________?

A: higher value B: ower value C: same value D: any value

Q28 : The radius of a dished head is taken approximately as______________________?

A: one-fourth B: half C: one D: two

Q29 :

A: What is the most common valve used in piping systems to throttle or regulate flow ? B: Globe valve C: Gate valve D: Butterfly valve

Q30 : A model of torpedo is tested in a towing tank at a velocity of 25 m/sec. The prototype is expected to attain a velocity of 5 m/sec. What model scale has been used ?

A: 1 : 5 B: 1 : 2.5 C: 1 :25 D: 1:V5″

Q31 : The flow which neglects changes in a transverse direction is known as_________________?

A: one dimensional flow B: uniform flow C: steady flow D: turbulent flow

Q32 : Select the correct statement?

A: Local atmospheric pressure depends upon elevation of locality only B: Standard atmospheric pressure is the mean local atmospheric pressure a* sea level C: Local atmospheric pressure is always below standard atmospheric pressure D: A barometer reads the difference be-tween local and standard atmospheric pressure

Q33 : Alcohol is used in manometer, because____________________?

A: its vapour pressure is low B: it provides suitable meniscus for the inclined tube C: its density is less D: it provides longer length for a given pressure difference

Q34 : Which of the following is mostly used used as blast furnace fuel for extracting pig iron from iron ores?

A: Brown coal B: Anthracite coal C: Hard coke D: Hard coke

Q35 : The depth of the center of pressure on a vertical rectangular gate 8 m wide and 6 m high, when the water surface coincides with the top of the gate, is____________________?

A: 2.4 m B: 3.0 m C: 4.0 m D: ”2.5 m

Q36 : For burning 1 kg of carbon to CO as per chemically correct combusiton, amount of air required is___________________?

A: 1 kg B: 4/3kg C: 8/3kg D: 16/3 kg

Q37 : Pulverized fuel is used for___________________?

A: better burning B: more calorific value C: less radiation loss D: medium sized units

Q38 : With increase in load, radiant super heater has____________________?

A: drooping characteristic B: lihear characterisstic C: rising characteristic D: flat characteristic

Q39 : Piezometer is used to measure_____________________?

A: pressure in pipe, channels etc. B: atmospheric pressure C: very low pressures D: difference of pressure between two points

Q40 : Presence of moisture in fuel oil would____________________?

A: keep the burner tips cool B: aid in proper combustion C: cause sputtering, possibly extinguish¬ing flame D: clean the nozzles

Q41 : 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

Q42 : The efficiency of the ideal diesel cycle is ________ than that of Otto cycle, for the same compression ratio

A: Higher B: Lower C: Equal D: None of these

Q43 : Pick up the wrong statement about water tube boiler in comparison to fire tube boilers ______________________?

A: former generates steam at high pressure B: former occupies less space for same power C: rate of steam flow is more in former case D: chances of explosion are less in former case

Q44 : Center of pressure compared to e.g. is___________________?

A: above it B: below it C: at same point D: above or below depending on area of body

Q45 : Center of pressure on an inclined plane is___________________?

A: at the centroid B: above the centroid C: below the centroid D: at metacentre

Q46 : Heating wet steam at constant temperature is heating it at constant_________________?

A: volume B: pressure C: entropy D: enthalpy

Q47 :

A: B: C: D:

Q48 : The proximate analysis of fuel lists__________________?

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

Q49 : Equivalent evaporation is the amount of water evaporated in a boiler from and at ____________________?

A: 0°C B: 100°C C: saturation temperature at given pressure D: room temperature

Q50 : Gardually increasing temperature of flue gases at inlet to chimney for given steam outputs is an indication of__________________?

A: higher effectiveness of boiler B: high calorific value coal being burnt C: fouling of heat transfer surfaces D: raising of steam temperature

Q51 : The difference between cornish boiler and lancashire boiler is that_________________?

A: former is fire tube type and latter is water tube type boiler B: former is water tube type and latter is fire tube type C: former contains one fire tube and latter contains two fire tubes D: none/of the above

Q52 : Which tool is used to measure gap size in a rough alignment?

A: Inside caliper B: . Dial indicator C: Feeler gage D: Measuring tape

Q53 : A packaged boiler is one in which various parts like firing equipment, fans, feed pumps and automatic controls are________________?

A: supplied by same manufacturer loose and assembled at site B: supplied mounted on a single base C: purchased from several parties and packed together at site D: packaged boiler does not exist

Q54 : In a free vortex motion, the radial component of velocity everywhere is________________?

A: maximum B: minimum C: zero D: non-zero and finite

Q55 : The number of drums in Benson steam generator is_________________?

A: one B: two C: one steam drum and one water drum D: no drum

Q56 : 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

Q57 : Pick up false statement?

A: For petrol and large gas engines, quantity governingds preferred B: In quantity governing, air fuel ratio is almost constant and quantity of charge is changed depending on load C: In hit and miss governing, fuel supply is completely cut off during one or more number of cycles D: In quality governing, quantity of fuel is varied to suit the load and total charge of air is varied

Q58 : With increase in load, convection superheater has_______________________?

A: drooping characteristic B: linear characterisstic C: rising characteristic D: flat characteristic

Q59 : Which of the following gases has the highest calorific value ________________?

A: producer gas B: coal gas C: water gas D: blast furnace gas

Q60 : 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: more than the tallest building nearby

Q61 : Pressure of the order of 10″‘ torr can be measured by__________________?

A: Bourdon tube B: Pirani Gauge C: micro-manometer D: ionisastion gauge

Q62 : The water tubes in a babcock and wilcox boiler are__________________?

A: horizontal B: vertical C: inclined D: horizontal and inclined

Q63 : The biggest size of thermal power unit operating in India is ________________?

A: 30 MW B: 60 MW C: 100 MW D: 500 MW

Q64 : 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

Q65 : Fire 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: forced circulation takes place D: tubes are laid vertically

Q66 : The two important forces for a floating body are__________________?

A: buoyancy, gravity B: buoyancy, pressure C: buoyancy, inertial D: inertial, gravity

Q67 : 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

Q68 : Which is not the correct statement about moisture in coal ______________________?

A: inherent moisture and surface mois¬ture are different things B: in some coals moisture may be present upto 40% C: some moisture in coal helps in better burning which is not possible with completely dry coal D: it increases thermal efficiency

Q69 : 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

Q70 : In a recuperative air preheater, the heat is transferred____________________?

A: from a metal wall from one medium to another B: from heating an itermediate material and then heating the air from this material C: by direct mixing , D: heat is transferred by bleeding some gases from furnace

Q71 : The pressure of reheat steam after passing through reheater compared to inlet condition is _________________?

A: more B: less C: equal D: . may be more or less depending on capacity of reheater

Q72 : The height of chimney in a power plant is governed by__________________?

A: the draft to be created B: limitation of construction facilities C: control of pollution D: quantity of flue gases to be handled

Q73 : In regenerative air preheater, the heat is transferred _____________________?

A: from a metal wall from one medium to another B: from heating an intermediateanaterial and then heating the air from this materia C: by direct mixing D: heat is transferred by bleeding some gas from furnace

Q74 : The evaporation of 15.653 kg of water per hour from and at 100°C is called_________________?

A: evaporative capacity B: factor of evaporation C: equivalent evaporation D: one boiler h.p.

Q75 : Thermal efficiency of a thermal power plant is of the order of____________

A: 15% B: 20% C: 30% D: 45%

Q76 : Hard coke is used in________________?

A: cement industry B: thermal power plant C: blast furnace D: domestic use

Q77 : 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

Q78 : Water boils when its vapour pressure ___________________?

A: equals that of the surroundings B: equals 760 mm of mercury C: equals to atmospheric pressure D: equals the pressure of water in the container

Q79 : Latent heat of dry steam at atmospneric pressure is equal to____________________?

A: 539 kcal/kg B: 539 BTU/lb C: 427 kcal/kg D: 100 kcal/kg

Q80 : A wet vapour can be completely specified by__________________?

A: pressure only B: temperature only C: dryness fraction only D: pressure and dryness fraction

Q81 : The feed check valve is used in order to ______________________?

A: regulate flow of boiler water B: check level of water in boiler drum C: recirculate unwanted feed water D: allow high pressure feed water to flow to drum and not allow reverse flow to take place

Q82 : Fluid is a substance that___________________?

A: cannot be subjected to shear forces B: always expands until it fills any container C: has the same shear stress.at a point regardless of its motion D: cannot remain at rest under action of any shear force

Q83 : The overall efficiency of thermal power plant is________________?

A: boiler efficiency, turhine efficiecny, generator efficiency B: all the three above plus gas cycle efficiency C: carnot cycle efficiency D: regenerative cycle efficiency

Q84 : Vacuum for reciprocating steam engines compared to steam turbines is__________________?

A: more B: equal C: less D: could be more or less depending on the size of plant

Q85 : True one-dimensional flow occurs when_________________?

A: the direction and magnitude of the veiocity at all points are identical B: the velocity of successive fluid par-ticles, at any point, is the same at suc-cessive periods of time C: the magnitude and direction of the velocity do not change from point to point in the fluid D: the fluid particles move in plane or parallel planes and the streamline pat-terns are identical in each plane

Q86 : On Millier chart, the constant pressure lines_________________?

A: diverge from left to right B: diverge from right to left C: are equally spaced throughout D: first rise up and then fall

Q87 : Total pressure on a lmxlm gate immersed vertically at a depth of 2 m below the free water surface will be_______________?

A: 1000 kg B: 4000 kg C: 2000 kg D: 8000 kg

Q88 : Efficiency of a thermal cycle increases by ________________?

A: regeneration B: reheating of steam C: both A. and B D: cooling of steam

Q89 : Which of the following coals has the highest calorific value_________________?

A: anthracite coal B: bituminous coal C: lignite D: peat

Q90 : While steam expands in turbines, theoretically the entropy________________?

A: remains constant B: increases C: decreases D: behaves unpredictably

Q91 : W, P and F all on one side

A: inductance B: voltage C: capacitance D: None of these

Q92 : 1 kg.m is equal to_________________?

A: 9.81 Joules B: All Joules C: D: 427 Joules

Q93 : The region between the separation streamline and the boundary surface of the solid body is known as__________________?

A: wake B: drag C: lift D: boundary layer

Q94 : For combustion of a fuel, following is essential_____________________?

A: correct fuel air ratio B: proper ignition temperature C: 02 to support combustion D: all the three above

Q95 : Free surface of a liquid behaves like a sheet and tends to contract to smallest possible area due to the_________________?

A: force of adhesion B: force of cohesion C: force of friction D: force of diffusion

Q96 : The total pressure force on a plane area is equal to the area multiplied by the intensity of pressure at the centriod, if___________________?

A: the area is horizontal B: the area is vertical C: the area is inclined D: all of the above

Q97 : Duplex feed pumps are used in small steam boilers. These operate on the principle of_________________?

A: centrifugal pump B: axial flow pump C: gear pump D: ejector pump

Q98 : Heating of dry steam above saturation temperature is known as_____________________?

A: enthalpy B: superheating C: supersaturation D: latent heat

Q99 : The balanced draft furnace is one using _________________________?

A: induced draft fan and chimney B: induced draft fan and forced draft fan C: forced draft fan and chimney D: any one of the above

Q100 : A boiler in India should conform to safety regulations of__________________?

A: DIN B: BS C: ASTM D: IBR

Free Mechanical Engineering MCQs Mock Test Online with Answers

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