Explore topic-wise MCQs in Mechanical Engineering Questions.

This section includes 371 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.

1.

The ultimate 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
E. moisture and ash free heating value
Answer» C. fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash
Discussion
2.

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. babcock and wilcox boiler
E. stoker fired boiler
Answer» D. babcock and wilcox boiler
Discussion
3.

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
E. air fed to pulverisers
Answer» B. transport and dry the coal
Discussion
4.

The number of drums in Benson steam generator is_________________?
A. one
B. two
C. one steam drum and one water drum
D. no drum
E. none of the above
Answer» E. none of the above
Discussion
5.

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. supply air for ignitors
E. convert CO (formed in lower zone of furnace) into C02 at higher zone
Answer» F.
Discussion
6.

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
E. rough analysis
Answer» C. higher calorific value
Discussion
7.

Thermal efficiency of well maintained boiler will be of the order___________________?
A. 20%
B. 40%
C. 50%
D. 75%
E. 90%
Answer» F.
Discussion
8.

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. vertical water tube type
E. forced circulation type
Answer» F.
Discussion
9.

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
E. reduce flame length
Answer» D. clean the nozzles
Discussion
10.

In a throttling process________________?
A. steam temperature remaisn constant
B. steam pressure remains constant
C. steam enthalpy remains constant
D. steam entropy remains constant
E. steam volume remains constant
Answer» D. steam entropy remains constant
Discussion
11.

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
E. none of the above
Answer» C. remain as it was
Discussion
12.

The bituminous coal is non-caking if its carbon content is_______________?
A. 78-81%
B. 81-85%
C. 85-90%
D. 90-95%
E. 95-100%.
Answer» B. 81-85%
Discussion
13.

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
E. none of the above
Answer» B. diverge from right to left
Discussion
14.

On Mollier chart, flow through turbine is represented by ________________?
A. horizontal straight line
B. vertical straight line
C. straight inclined line
D. curved line
E. none of the above
Answer» C. straight inclined line
Discussion
15.

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
E. none of the above
Answer» B. separating calorimeter
Discussion
16.

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
Answer» D. none/of the above
Discussion
17.

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
E. at the inlet of chimney
Answer» E. at the inlet of chimney
Discussion
18.

Caking coals are those which __________________________?
A. form lumps or masses of coke
B. burn freely
C. show little or no fusing action
D. burn completely
E. do not form ash
Answer» B. burn freely
Discussion
19.

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. equivalent evaporation
E. boiler efficiency
Answer» F.
Discussion
20.

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
E. remove molten aslj
Answer» D. control steam dome
Discussion
21.

Fusible plug for boilers is made of fusible metal containing tin, lead, and___________________?
A. bismuth
B. copper
C. aluminium
D. nickel
E. iron
Answer» B. copper
Discussion
22.

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. former is used for high installed capacity
E. chances of explosion are less in former case
Answer» F.
Discussion
23.

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 mixtur
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
E. heating of water takes place in stages
Answer» D. water is converted into steam in one pass without any recirculation
Discussion
24.

In accelerated circulation type boiler________________?
A. heating takes place at bottom and the water supplied at bottom gets converted into the mixture of stdam bubbles and hot water which rise to durm
B. water is supplied in drum and through downcomers” located in atmospheric conditon it passes to the water wall and rises to durm in the from of mixtu
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
E. water is fed under high pressure and high velocity
Answer» C. feed pump is employed to supplement natural circulation in water wall type furnace
Discussion
25.

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
E. none of the above is true
Answer» B. is raisd at slower rate
Discussion
26.

Reheating of steam under ideal conditions takes place at constant __________________?
A. entropy
B. enthaply
C. pressure
D. temperature
E. all of the above
Answer» E. all of the above
Discussion
27.

Expanding steam to a very low pressure (high vacuum) in steam engines is _________________?
A. desirable
B. economical
C. essential
D. optional
E. uneconomical
Answer» F.
Discussion
28.

Boiler stays are used to___________________?
A. prevent flat surfaces under pressure from tearing apart
B. take care of failure in shear
C. take care of failure in compression
D. provide support for boiler
E. provide foundation of boiler
Answer» B. take care of failure in shear
Discussion
29.

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
E. outside diameter alone
Answer» D. outside diameter and inside diameter
Discussion
30.

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 material
C. by direct mixing
D. heat is transferred by bleeding some gas from furnace
E. none of the above
Answer» C. by direct mixing
Discussion
31.

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
E. None of the above
Answer» B. Lower calorific value at constant volume
Discussion
32.

The major axis of elliptical manholes on the shell should be provided___________________?
A. longitudinally
B. circumferentially
C. on dished end
D. anywhere
E. vertically
Answer» C. on dished end
Discussion
33.

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
E. supersaturated steam
Answer» E. supersaturated steam
Discussion
34.

With increase in load, radiant super heater has____________________?
A. drooping characteristic
B. linear characterisstic
C. rising characteristic
D. flat characteristic
E. none of the above
Answer» B. linear characterisstic
Discussion
35.

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
E. 15 cm
Answer» C. 8 cm
Discussion
36.

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
E. none of the above
Answer» E. none of the above
Discussion
37.

Pulverized fuel is used for___________________?
A. better burning
B. more calorific value
C. less radiation loss
D. medium sized units
E. stoker fired boilers
Answer» B. more calorific value
Discussion
38.

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
E. to heat feed water by bled steam
Answer» B. economise on fuel
Discussion
39.

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
E. none of the above
Answer» C. equal
Discussion
40.

The safety valve at superheater as compared to drum safety valve setting is set at___________________?
A. higher value
B. lower value
C. same value
D. any value
E. none of the above
Answer» C. same value
Discussion
41.

Steam exhaust from high pressure turbine is reheated in _____________________?
A. boiler drum
B. superheater tubes
C. economiser
D. a separate coil
E. a separate coil located in convection path
Answer» F.
Discussion
42.

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
Answer» B. (1 + moisture content)
Discussion
43.

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
E. none ot the above
Answer» C. convert CO (formed in lower zone of furnace) into C02 at higher zone
Discussion
44.

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
E. filtering
Answer» B. cooling the oil in the settling tanks
Discussion
45.

02 content in atmospheric air on volume basis is___________________?
A. 21%
B. 23%
C. 30%
D. 40%
E. 70%
Answer» B. 23%
Discussion
46.

Evaporative capacity of boiler is expressed as____________________?
A. kg of steam produced
B. steam pressure produced
C. kg of fuel fired
D. kg of steam produced per kg of fuel fifed
E. kg of water evaporated
Answer» E. kg of water evaporated
Discussion
47.

Incomplete combustion can be best judged by__________________?
A. smoky chimney exit
B. excess air in flue gases
C. measuring carbon mono-oxide in flue gases
D. measuring temperature of flue gases at exit of furnace
E. measuring oxygen in flue gases
Answer» D. measuring temperature of flue gases at exit of furnace
Discussion
48.

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
E. none of the above
Answer» C. forced draft fan and chimney
Discussion
49.

Maximum energy loss in a boiler occurs due to _______________________?
A. unburnt carbon in ash
B. incomplete combustion
C. ash content
D. flue gases
E. radiation losses
Answer» E. radiation losses
Discussion
50.

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
E. heat consumed in evaporating 1 kg water at 0°C to steam at 100°C and 1.033 kg/cm pressure
Answer» D. work done by 1 kg of steam at saturation condition
Discussion