Free Mechanical Engineering MCQs Mock Test Online with Answers

Q1 : The buoyancy depends on___________________?

A: mass of liquid displaced B: viscosity of the liquid C: pressure of the liquid displaced D: depth of immersion

Q2 : The patrol is distilled at a temperature from :

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

Q3 : To avoid vaporisation in the pipe line, the pipe line over the ridge is laid such that it is not more than____________________?

A: 2.4 m above the hydraulic gradient B: 6.4 m above the hydraulic gradient C: 10.0 m above the hydraulic gradient D: 5.0 above the hydraulic gradient

Q4 : For very great pressures, viscosity of moss gases and liquids__________________?

A: remains same B: increases C: decreases D: shows erratic behavior

Q5 : 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

Q6 : 1 kg.m is equal to_________________?

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

Q7 : Mach number is significant in_____________________?

A: supersonics, as with projectiles and jet propulsion B: full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc. C: simultaneous motion through two fluids where there is a surface of dis-continuity, gravity force, and wave making effects, as with ship’s hulls D: all of fhe above

Q8 : The pressure at which latent heat of vaporisation of water is zero, is_________________?

A: 225.6 kg/cm2 B: 1 kg/cm2 C: 100 kg/cm2 D: 170 kg/cm2

Q9 : Adiabatic process is________________?

A: essentially an isentropic process B: non-heat transfer process C: reversible process D: constant temperature process

Q10 : 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

Q11 : Bernoulli equation deals with the law of conservation of__________________?

A: mass B: momentum C: energy D: work

Q12 : The bulk modulus of elasticity___________________?

A: has the dimensions of 1/pressure B: increases with pressure C: is large when fluid is more compressible D: is independent of pressure and viscosity

Q13 : The condition of steam in boiler drum is always ___________________?

A: dry B: wet C: saturated D: supersaturated

Q14 : Which device is used in thermal power plants to reduce level of pollution___________________?

A: induced draft fan B: smoke meter C: chimney D: precipitator

Q15 : Uniform flow occurs when_____________________?

A: the direction and magnitude of the velocity at all points are identical B: the velocity of successive fluid paiticles, at any point, is the same at successive 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 pleasure

Q16 : 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

Q17 : Primary air is the air used to__________________?

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

Q18 : The basic job of feed water treatment in boilers is to overcome the problem of __________________?

A: corrosion B: scale C: carryover D: all of the above

Q19 : In locomotives, the draught is produced by_________________?

A: chimney B: induced draft fan C: both combined A. and B. D: steam jet draught

Q20 : Orsat meter is used for__________________?

A: gravimetric analysis of the flue gases B: volumetric analysis of the flue gases C: mass flow of the flue gases D: measuring smoke density of flue gases

Q21 : In a free vortex motion, the radial component of velocity everywhere is________________?

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

Q22 : The behaviour of coal in a furnace is determained by_______________________?

A: the content of sulphur B: the content of ash and heating value C: the proximate analysis D: the exact analysis

Q23 : In the lever of third order, load W, effort P and fulcrum F are oriented as follows_________________?

A: W between P and F B: F between W and P C: P between W and F D: W, P and F all on one side

Q24 : 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

Q25 : The diameter of fire tubes in Cochran boiler is of the order of___________________?

A: 2 cm B: 6 Cm C: 8 cm D: 12 cm

Q26 : 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

Q27 : 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

Q28 : For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has ____________________?

A: more heating surface B: less heating surface C: equal heating surface D: heating surface depends on other parameters

Q29 : Specific weight of sea water is more that of pure water because it contains_________________?

A: dissolved air B: dissolved salt C: suspended matter D: all of the above

Q30 : 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

Q31 : 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

Q32 : Which of the following substance will have same percentage in both proximate and ultimate analysis___________________?

A: ash B: volatile matter C: moisture D: . hydrogen

Q33 : The function of injector used in small steam plants is to________________?

A: create vacuum in furnace B: create vacuum at turbine exhaust C: pump feed water D: dose chemicals in feed water

Q34 : The state of vapour under saturation condition is described by_______________?

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

Q35 : Which is not correct statement about effect of sulphur in fuel ___________________?

A: it has heating value B: it helps in electrostatic precipitation of ash in flue-gases C: it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low D: it erodes furnace walls

Q36 : 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

Q37 : 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

Q38 : Ultimate analysis of fuel is determination of percentage of____________________?

A: carbon, hydrogen, nitrogen, sulphur, moisture B: . fixed carbon, ash, volatile matter, moisture C: higher calorific value D: best analysis

Q39 : 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

Q40 : In the case of steady flow of a fluid, the acceleration of any fluid particle is________________?

A: constant B: variable C: zero D: zero under limiting conditions

Q41 : 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

Q42 : Steam in water tube boiler as compared to fire tube boiler_________________?

A: can be raised rapidly B: is raisd at slower rate C: is raised at same rate D: could be raised at fast/slow rate depending on design

Q43 : The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is__________________?

A: less B: more C: equal D: may be less or more depending on temperature

Q44 : 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

Q45 : The centre of gravity of the volume of the liquid displaced by an immersed body is called ___________________?

A: centre of gravity B: centre of pressure C: metacentre D: centre of buoyancy

Q46 : Which tool is used to measure gap size in a rough alignment?

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

Q47 : Center of pressure on an inclined plane is___________________?

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

Q48 : 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

Q49 : On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by_______________?

A: horizontal straight line B: vertical straight line C: straight inclined line D: none of the above

Q50 : Boiler stays are used to___________________?

A: prevent flat surfaces under pressure from tearing apartprovide support for boiler B: take care of failure in shear C: take care of failure in compression D: provide support for boiler

Q51 : The specific weight of water is 1000 kg/m”_________________?

A: at normal pressure of 760 mm B: at 4°C temperature C: at mean sea level D: all the above

Q52 : The diameter of fire tube of Cornish boiler compared to its shell is__________________?

A: one half B: one third C: one-fifth D: two-fifth

Q53 : Sulphur in coal results in___________________?

A: causing clinkering and slagging B: corroding air heaters C: spontaneous combustion during coal storage D: all of the above

Q54 : The radius of a dished head is taken approximately as______________________?

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

Q55 : The specific heat of superheated steam in kcal/kg is generally of the order of___________________?

A: 0.1 B: 0.3 C: 0.5 D: 1.0

Q56 : Which is not correct statement about pulverised fuel firing ?

A: high burning rate is possible B: heat release can be easily controlled C: fuel burns economically D: it is the best technique for burning high ash content fuel having low fusion ash

Q57 : An economiser in a boiler______________________?

A: increases steam pressure B: increases steam flow C: decreases fuel consumption D: decreases steam pressure

Q58 : Ball valves are commonly used to_________?

A: throttle flow B: check flow C: change flow direction D: start/stop flow

Q59 : Rotameter is a device used to measure______________?

A: absolute pressure B: velocity of fluid C: flow D: rotation

Q60 : 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

Q61 : The total pressure on the surface of a vertical sluice gate 2 m x 1 m with its top 2 m surface being 0.5 m below the water level will be ________________?

A: 500 kg B: 1000 kg C: 1500 kg D: 2000 kg

Q62 : The bituminous coal is non-caking if its carbon content is_______________?

A: 78-81% B: 81-85% C: 85-90% D: 90-95%

Q63 : In designing air preheater, the important design consideration is that_________________?

A: approach temperature should be as low as possible B: handling and maintenance should be easier C: heat transfer area should be optimum D: heat transfer area should be optimum

Q64 : The property of a fluid which enables it to resist tensile stress is known as___________________?

A: compressibility B: surface tension C: cohesion D: adhesion

Q65 : 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

Q66 : 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

Q67 : Property of a fluid by which its own molecules are attracted is called___________________?

A: adhesion B: cohesion C: viscosity D: compressibility

Q68 : Water and sediment in fuel oil can be removed by _______________________?

A: heating the oil in the settling tanks B: cooling the oil in the settling tanks C: burning the oil D: suspension

Q69 : If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by___________________?

A: throttling calorimeter B: separating calorimeter C: combined separating and throttling calorimeter D: bucket calorimeter

Q70 : The safety valve on boiler drum compared to safety valve on super heater is set at ________________?

A: same value B: higher value C: lower value D: lower/higher depending on steam flow

Q71 : Locomotive boiler is of the following type__________________?

A: multitubular B: horizontal C: internally fired D: all of the above

Q72 : 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

Q73 : Density of water is maximum at__________________?

A: 0°C B: 0°K C: 4°C D: 4°C

Q74 : Pick up the wrong statement about critical condition of steam___________________?

A: latent heat is zero B: liquid directly becomes steam C: specific volume of steam and liquid is same D: this is the maximum pressure limit

Q75 : Pick up wrong statement about desired properties of a good fuel__________________?

A: high calorific value B: produce minimum smoke and gases C: ease in storing D: high ignition point

Q76 : 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

Q77 : Two pipe systems can be said to be equivalent, when the following quantities are same__________________?

A: friction loss and flow B: length and diameter C: flow and length D: friction factor and diameter

Q78 : W, P and F all on one side

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

Q79 : The change in internal energy in steam engines equals to__________________?

A: work done during the rankine cycle ; B: work done during compression. C: work done during adiabatic expansion D: change in enthalpy

Q80 : The saturation temperature of steam with increase in pressure increases____________________?

A: inearly B: rapidly first and then slowly C: slowly first and then rapidly D: inversely

Q81 : Efficiency of a thermal cycle increases by ________________?

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

Q82 : The diameter of internal flue tubes in a Lancashire boiler compared to its shell is_________________?

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

Q83 : 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

Q84 : Diesel Cycle is also known as : __________?

A: Constant temperature cycle B: Constant Volume cycle C: Constant Pressure Cycle D: All of above

Q85 : Secondary air is the used to_________________?

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

Q86 : 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

Q87 : One kilowatt-hour energy is equivalent to ________________?

A: 1000 J B: 360 kJ C: 3600 kJ D: 3600 kW/sec

Q88 : Thermal efficiency of well maintained boiler will be of the order___________________?

A: 20% B: 40% C: 50% D: 90%

Q89 : 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

Q90 : 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

Q91 : Choose the wrong statement?

A: The horizontal component of the hydro-static force on any surface is equal to the normal force on the vertical projection of the surface B: The horizontal component acts through the center of pressure for the vertical projection C: The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area D: he vertical component passes through the center of pressure of the volume

Q92 : With increase in load, radiant super heater has____________________?

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

Q93 : 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

Q94 : The coal requirement per kW hour generation in the thermal power plant is of the order of__________________?

A: 0.1 to 0.2 kg B: 0.2 to 0.4 kg C: 0.6 to 0.8 kg D: 1.0 to 1.5 kg

Q95 : The ratio of absolute viscosity to mass density is known as_________________?

A: specific viscosity B: viscosity index C: kinematic viscosity D: coefficient of viscosity

Q96 : The natural solid fuels are : ________?

A: Wood B: Peat C: Peat D: All of above

Q97 : The fusible plug in small boilers is located ________________?

A: in the drum B: in the fire tubes C: above steam dome D: over the combustion chamber

Q98 : The process of diffusion of one liquid into the other through a semi-permeable membrane is called_______________________?

A: viscosity B: osmosis C: diffusivity D: surface tension

Q99 : The difference of pressure between the inside and outside of a liquid drop is _______________?

A: p = Txr B: p = T/r C: p = T/2r D: p = 2T/r

Q100 : 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

Free Mechanical Engineering MCQs Mock Test Online with Answers

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