Free Mechanical Engineering MCQs Mock Test Online with Answers

Q1 : 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

Q2 : Rotameter is a device used to measure______________?

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

Q3 : 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

Q4 : Euler’s dimensionless number relates the following__________________?

A: inertial force and gravity B: viscous force and inertial force C: viscous force and buoyancy force D: pressure force and inertial force

Q5 : 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.

Q6 : 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

Q7 : During the opening of a valve in a pipe line, the flow is_________________?

A: steady B: unsteady C: uniform D: free vortex type

Q8 : Adiabatic process is________________?

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

Q9 : Fire tube boilers are limited to a maximum design working pressure of ____________________?

A: 1 kg/cm B: 6 kg/cm C: 17 kg/cm2 D: 100 kg/cm2

Q10 : The number of drums in Benson steam generator is_________________?

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

Q11 : 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

Q12 : Pour point of fuel oil is the____________________?

A: lowest temperature at which oil will flow under set condition B: storage temperature C: temperature at which fuel is pumped through burners D: lowest temperature at which oil will flow under set condition

Q13 : Water 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: work is done during adiabatic expansion D: change in enthalpy

Q14 : 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

Q15 : 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

Q16 : W, P and F all on one side

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

Q17 : At which pressure the properties of water and steam become identical_________________?

A: 0.1 kg/cm2 B: 1 kg/cm2 C: 100 kg/cm2 D: 225.6 kg/cm2

Q18 : The heat loss in a boiler takes place in the form of________________?

A: heat carried away by flue gases B: heat carried away by ash C: moisture present in fuel and steam formed by combustion of hydrogen in fuel D: all of the above

Q19 : Fusible plug for boilers is made of fusible metal containing tin, lead, and___________________?

A: bismuth B: copper C: aluminium D: nickel

Q20 : 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

Q21 : The hydraulic turbines are also known as : ___________?

A: steam turbines B: water turbines C: combustion turbines D: Gas turbines

Q22 : 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

Q23 : 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

Q24 : In a free vortex motion, the radial component of velocity everywhere is________________?

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

Q25 : 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

Q26 : 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

Q27 : 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

Q28 : With increase in load, radiant super heater has____________________?

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

Q29 : Choose the wrong statement ?

A: any weight, floating or immersed in a liquid, is acted upon by a buoyant force B: Buoyant force is equal to the weight of the liquid displaced C: The point through which buoyant force acts, is called the center of buoyancy D: Center of buoyancy is located above the center of gravity of the displaced liquid v

Q30 : Feed water conditioning in thermal power plants in done to__________________?

A: reduce hardness and for removal of solids B: increase efficiency-of thermal power plant C: increase *heat transfer rate D: increase steam parameters

Q31 : 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

Q32 : The hydraulic turbines are also known as : ___________?

A: steam turbines B: water turbines C: combustion turbines D: Gas turbines

Q33 : Which tool is used to measure gap size in a rough alignment?

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

Q34 : 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

Q35 : 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

Q36 : The three “Ts” for good combustion are____________________?

A: The three “Ts” for good combustion are____________________? B: total air, true fuel, and turbulance C: thorough mixing, total air, and temperature D: total air, time, and temperature

Q37 : 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

Q38 : 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

Q39 : What is the weight (in lbf) of one gallon of air at 1 atm and 25˚C? The molecular mass of air is 28.97 g/mole = 0.02897 kg/mole

A: 90 lbf B: 65.78 lbf C: 0.00989 lbf D: 3.00989 lbf

Q40 : 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″

Q41 : 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

Q42 : In locomotives, the draught is produced by_________________?

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

Q43 : Deaeration of feed water is carried out because it reduces ____________________?

A: cavitation of . boiler feed pumps B: cavitation of . boiler feed pumps C: heat transfer coefficient D: . pH value of water

Q44 : A fusible plug is fitted in small boilers in order to ___________________?

A: avoid excessive build up of pressure B: avoid explosion C: extinguish fire if water level in the boiler falls below alarming limit D: control steam dome

Q45 : 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

Q46 : Efficiency of rankine cycle can be increased by_________________?

A: decreasing initial steam pressure and temperature B: increasing exhaust pressure C: decreasing exhaust pressure D: increasing the expansion ratio

Q47 : Mechanical equivalent of heat for 1 kcal or Joule’s equivalent is equal to_________________?

A: 421 kgm B: 421 kgm C: 539 kgm D: 102 kgm

Q48 : 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

Q49 : 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

Q50 : 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

Q51 : 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

Q52 : Which of the following gases has the highest calorific value ________________?

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

Q53 : Calorific value of coal is of the order of _______________________?

A: 200-400 kcal/kg B: 800-1200 kcal/kg C: 2000-4000 kcal/kg D: 5000-8000 kcal/kg

Q54 : 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

Q55 : An object having 10 kg mass weighs 9.81kg on a spring balance. The value of ‘g’ at this place is _________________?

A: 10m/sec2 B: 9.81 m/sec2 C: 10.2/m sec D: 9.75 m/sec2

Q56 : 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

Q57 : 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

Q58 : Working principle of dead weight pressure gauge tester is based on_______________?

A: Pascal’s law B: Dalton’s law of partial pressure C: Newton’s law of viscosity . D: Avogadro’s hypothesis

Q59 : 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

Q60 : 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: fuel bed firing

Q61 : 1 kg.m is equal to_________________?

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

Q62 : 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

Q63 : 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

Q64 : In natural 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 durm and through down-comers located in atmospheric conditon 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

Q65 : Ball valves are commonly used to_________?

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

Q66 : The ratio of absolute viscosity to mass density is known as_________________?

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

Q67 : 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

Q68 : Which of the following manometer has highest sensitivity_________________?

A: U-tube with water B: inclined U-tube C: U-tube with mercury D: micro-manometer with water

Q69 : 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

Q70 : Which of the following solid fuel has high caloric value : ___________?

A: Wood B: Peat C: Bituminous coal D: Anthracite coal

Q71 : 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

Q72 : Thermal efficiency of well maintained boiler will be of the order___________________?

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

Q73 : Two dimensional flow occurs when________________?

A: the direction and magnitude of the velocity at all points are identical B: the velocity of successive fluid particles, 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 plane

Q74 : Hard coke is produced by carborisation of coal at_______________?

A: atmospheric temperature B: 500-600°C C: 70O-850°C D: 95O-1100°C

Q75 : Choose the correct relationship ?

A: specific gravity = gravity x density B: dynamicviscosity = kinematicviscosity x density C: gravity = specific gravity x density D: kinematicviscosity = dynamicviscosity x density

Q76 : The major axis of elliptical manholes on the shell should be provided___________________?

A: longitudinally B: circumferentially C: on dished end D: anywhere

Q77 : A safety valve in a locomotive starts leaking. The leaking medium will be_________________?

A: water B: dry steam C: wet steam D: super heated steam

Q78 : 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

Q79 : 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

Q80 : Center of pressure on an inclined plane is___________________?

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

Q81 : 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

Q82 : Which of the following is a water tube boiler_________________?

A: locomotive boiler B: Cochran boiler C: Cornish boiler D: Babcock and Wilcox boiler

Q83 : Reheating of steam under ideal conditions takes place at constant __________________?

A: entropy B: enthaply C: pressure D: temperature

Q84 : The property of a fluid which enables it to resist tensile stress is known as___________________?

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

Q85 : Property of a fluid by which its own molecules are attracted is called___________________?

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

Q86 : Pick up the correct statement as regards Cornish boiler and Lancashire boiler _______________?

A: cornish is fire tube and lancashire is water tube B: cornish is water tube and lancashire is fire tube C: cornish has two fire tubes and lancashire has one D: lancashire has two fire tubes and cornish has one

Q87 :

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

Q88 : Newton’s law of viscosity is a relationship between____________________?

A: shear stress anctthejiate of angular distortion B: shear stress and viscosity C: shear stress, velocity and viscosity D: shear stress, pressure and rate of angular distortion

Q89 : 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

Q90 : 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

Q91 : An economiser in a boiler______________________?

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

Q92 : 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

Q93 : 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: Woodchar coal

Q94 : 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

Q95 : 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

Q96 : 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.

Q97 : The equivalent evaporation of a boiler is a measure to compare _________________?

A: the given boiler with the model B: the two different boilers of the same make C: two different makes of boilers operat¬ing under the same operating conditions D: any type of boilers operating under any conditions

Q98 : Pick up the wrong statement?

A: aluminium in steel results in excessive grain growth B: manganese in steel induces hardness C: nickel and chromium in steel help in raising the elastic limit and improve the resilience and ductility D: tungsten in steels improves magnetic properties and hardenability

Q99 : Sublimation region is the region where__________________?

A: solid and vapour phases are in equi-librium B: solid and liquid phases are in equilibrium C: liquid and vapour phases are in equilibrium D: solid, liquid and vapour phases are in equilibrium

Q100 : 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

Free Mechanical Engineering MCQs Mock Test Online with Answers

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