Free Mechanical Engineering MCQs Mock Test Online with Answers

Q1 : In which of the following boilers, the draught in furnace is increased by utilising exhaust steam from engine__________________?

A: lancashire boiler B: locomotive boiler C: babcock and wilcox boiler D: cochran boiler

Q2 : Heating wet steam at constant temperature is heating it at constant_________________?

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

Q3 : Cochran boiler is a__________________?

A: horizontal fire-tube boiler B: horizontal water-tube boiler C: veritcal water-tube boiler D: vertical fire tube boiler

Q4 : Heating value of fuel used is as on fired basis. If it is reported for dry or moisture free fuel, then latter should be multiplied by the following factor to correct for as fired value ___________________?

A: (1- moisture content) B: (1 + moisture content) C: 1 + moisture content D: 1 – moisture content

Q5 :

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

Q6 : 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

Q7 : Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler _________________?

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

Q8 : 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

Q9 : The ratio of absolute viscosity to mass density is known as_________________?

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

Q10 : Falling drops of water become spheres due to the property of ____________________?

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

Q11 : Adiabatic process is________________?

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

Q12 : 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

Q13 : 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

Q14 : It is required to produce large amount of steam at low pressure. Which boiler should be used ?

A: pulverised fuel fired boiler B: cochran boiler C: lancashire boiler D: lancashire boiler

Q15 : 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

Q16 : The fire tubes in, a Coarran and Scotish marine boiler are_________________?

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

Q17 : Equivalent evaporation of water is the evaporation “for a feed water supply at 100°C__________________?

A: and its corresponding conversion into dry saturated steam at 100°C and 1.033 kg/cm2 B: and its corresponding conversion into dry steam at desired boiler pressure C: conversion into steam at atmospheric condition D: conversion into steam at the same pres-sure at which feed water is supplied

Q18 : Steam exhaust from high pressure turbine is reheated in _____________________?

A: boiler drum B: superheater tubes C: economiser D: a separate coil located in convection path

Q19 : 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

Q20 : In locomotives, the draught is produced by_________________?

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

Q21 : A piece of wood having weight 5 kg floats in water with 60% of its volume under the liquid. The specific gravity of wood is _________________?

A: 0.83 B: 0.6 C: 0.4 D: none of the above

Q22 : Which of the following is steam dbal?

A: non-coking bituminous coal B: brown coal C: coking bituminous coal D: none of the above

Q23 : Which of the following coals has the highest calorific value_________________?

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

Q24 : Center of pressure on an inclined plane is___________________?

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

Q25 : 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

Q26 : One kilowatt-hour energy is equivalent to ________________?

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

Q27 : Hygrometery deals with the_________________?

A: Hygroscopic substances B: water vapour in air C: temperature of air D: pressure of air

Q28 : Choose the wrong statement ?

A: The center of buoyancy is located at the center of gravity of the displaced liquid B. For stability of a submerged body, the center of gravity of body must lie directly below the center of buoyancy B: If e.g. and center of buoyancy coincide, the submerged body must lie at neutral equilibrium for all positions C: For stability of floating cylinders or spheres, the e.g. of body must lie below the center of buoyancy D: All floating bodies are stable

Q29 : Carbonation of coal is the process of________________________?

A: pulverising coal in inert atmosphere B: heating wood in a limited supply of air at temperatures below 300°C 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-ettes

Q30 : In forced circulation 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 : 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

Q32 : Stoichiometric quantity of air is the___________________?

A: air present in atmosphere at NTP conditions B: air required for complete combustion of fuel with no excess air C: air required for optimum combustion so as to have reasonable excess air D: air required to convert CO into C02

Q33 : 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

Q34 : 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

Q35 : While steam expands in turbines, theoretically the entropy________________?

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

Q36 : 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

Q37 : 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

Q38 : An odd shaped body weighing 7.5 kg and occupying 0.01 m3 volume will be completely submerged in a fluid having specific gravity of__________________?

A: 1 B: 1.2 C: 0.8 D: 0.75

Q39 : 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

Q40 : 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

Q41 : With increase in load, convection superheater has_______________________?

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

Q42 : An ideal regenerative cycle is ______________________?

A: equal to carnot cycle B: less than carnot cycle C: more than carnot cycle D: could be anything

Q43 : Which of the following solid fuel has high carbon content?

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

Q44 : When the flow parameters at any given instant remain same at every point, then flow is said to be___________________?

A: quasi static B: steady state C: laminar D: uniform

Q45 : A boiler in India should conform to safety regulations of__________________?

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

Q46 : 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

Q47 : 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

Q48 : 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

Q49 : 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

Q50 : 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

Q51 : One kg of steam sample contains 0.8 kg dry steam; it’s dryness fraction is__________________?

A: 0.2 B: 0.8 C: 1.0 D: 0.6

Q52 : Mercury is often used in barometer because____________________?

A: it is the best liquid B: the height of barometer will be less C: its vapour pressure is so low that it may be neglected D: both B. and C.

Q53 : 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

Q54 : Thermal efficiency of well maintained boiler will be of the order___________________?

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

Q55 : Proximate 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: lower calorific value

Q56 : 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

Q57 : The dry saturated steam at very low pressure, (5-10 kg/cm2) when throttled to atmosphere will become________________?

A: wet B: superheated C: remain dry satruated D: none of the above

Q58 : 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

Q59 : 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

Q60 : 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

Q61 : 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

Q62 : Density of water is maximum at__________________?

A: 0°C B: 0°K C: 4°C D: 4°C

Q63 : A ship whose hull length is 100 m is to travel at 10 m/sec. For dynamic similarity, at what velocity should a 1:25 model be towed through water ?

A: 10 m/sec B: 25 m/sec C: 2 m/sec D: 50 m/sec

Q64 : Pulverized fuel is used for___________________?

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

Q65 : 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

Q66 : Steam engine operates on_________________?

A: carnot cycle B: brayton cycle C: Stirling cycle D: joule cycle

Q67 : The economizer is used in boilers to _______________________?

A: increase thermal efficiency of boiler B: economise on fuel C: extract heat from the exhaust flue gases D: increase flue gas temperature

Q68 : 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

Q69 : The average calorific value of wood is about : __________?

A: 33500 kj/kg B: 25000 kj/kg C: 23000 kj/kg D: 19700 kj/kg

Q70 : 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

Q71 : 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

Q72 : The pressure in the air space above an oil (sp. gr. 0.8) surface in a tank is 0.1 kg/cm”. The pressure at 2.5 m below the oil surface will be __________________?

A: 2 metres of water column B: 3 metres of water column C: 3.5 metres of water column D: 4 m of water column

Q73 : 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

Q74 : The bituminous coal is non-caking if its carbon content is_______________?

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

Q75 : 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

Q76 : In locomotive boiler, maximum steam pressure is limited to_______________?

A: 1 kg/cm2 B: 5 kg/cm2 C: 10 kg/cm2 D: 18 kg/cm2

Q77 : Property of a fluid by which its own molecules are attracted is called___________________?

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

Q78 : Maximum energy loss in a boiler occurs due to _______________________?

A: unburnt carbon in ash B: incomplete combustion C: ash content D: flue gases

Q79 : 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

Q80 : 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

Q81 : 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

Q82 : 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

Q83 : 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

Q84 : Water at pressure of 4 kg/cm2 and 160°C temperature when exposed to atmosphere will_________________?

A: boil B: flash i.e. get converted into steam C: remain as it was D: cool down

Q85 : Units of surface tension are____________________?

A: energy/unit area B: distance C: both of the above D: it has no units

Q86 : 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

Q87 : Practical fluids___________________?

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

Q88 : 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

Q89 : For very great pressures, viscosity of moss gases and liquids__________________?

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

Q90 : The increase in pressure _________________?

A: lowers the boiling point of a liquid B: raises the boiling point of a liquid C: .does not affect the boiling point of a liquid D: reduces its volume

Q91 : Superheating of steam is done at_________________?

A: constant volume B: constant temperature C: constant temperature D: constant entropy

Q92 : The number of flue tubes in Lancashire boiler is_________________?

A: zero B: one C: two D: four

Q93 : 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

Q94 : 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

Q95 : The lenght of Cornish boiler is of the order of _________________?

A: 2-4 m B: 3-5 m C: 5-7.5 m D: 7-9 m

Q96 : The patrol is distilled at a temperature from :

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

Q97 : Diesel Cycle is also known as : __________?

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

Q98 : Locomotive boiler is of the following type__________________?

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

Q99 : 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

Q100 : 1 kg.m is equal to_________________?

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

Free Mechanical Engineering MCQs Mock Test Online with Answers

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