Steam Boilers, Engines, Nozzles and Turbines - Mechanical Engineering MCQs

Steam Boilers, Engines, Nozzles and Turbines -
Multiple Choice Questions and Answers

1. For water, at pressures below
atmospheric,
(a) melting point rises slightly and boiling
point drops markedly
(b) melting point rises markedly and boiling
point drops markedly
(c) melting point drops slightly and boiling
point drops markedly
(d) melting point drops slightly and boiling
point drops slightly
(e) none of the above.
Ans: a
2. At very low temperature, the melting
and boiling temperatures become equal. This
temperature is
(a) 373°K
(b) 273.16°K
(c) 303°K
(d) 0°K.
(e) 300°K.
Ans: b
3. 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
(e) - 1 kgf/cm2.
Ans: a
4. 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
(e) unpredictable.
Ans: a
5. The saturation temperature of steam
with increase in pressure increases
(a) linearly
(b) rapidly first and then slowly
(c) slowly first and then rapidly
(d) inversely
(e) none of the above.
Ans: b
6. Carbonisation 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
(e) enriching carbon in the coal.
Ans: c
7. 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
(e) enriching carbon in the coal.
Ans: c
8. Heating of dry steam above saturation
temperature is known as
(a) enthalpy
(b) superheating
(c) supersaturation
(d) latent heat
(e) super tempering.
Ans: b
9. Superheating of steam is done at
(a) constant volume
(b) constant temperature
(c) constant pressure
(d) constant entropy
(e) constant enthaply.
Ans: c
10. 1 kg.m is equal to
(a) 9.81 Joules
(b) All Joules
(c) 427 Joules
(d) 102 Joules
(e) 539 Joules.
Ans: a
11. If partial pressure of air and steam be
pa andps respectively in a condenser, then
according to Dalton's law, the pressure in
condenser is equal to
(a) Ps-Pa
(b) pa-ps
(C) Pa+P,
Ans: c
12. 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
(e) 20°C.
Ans: b
13. The specific volume of steam with
increase in pressure decreases
(a) linearly
(b) slowly first and then rapidly
(c) rapidly first and then slowly
(d) inversely
(e) none of the above.
Ans: c
14. 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) two boilers of same make but operaing
under different conditions
(e) any type of boilers operating under any
conditions.
Ans: e
15. 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
(e) 1.5 to 2 kg.
Ans: c
16. 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
(e) none of the above.
Ans: a
17. 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
(e) air required to form an explosive
mixture.
Ans: b
18. 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
(e) 0.5.
Ans: b
19. 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.
Ans: a
20. If xx and x2 be the dryess fractions
obtained in separating calorimeter and throttling
calorimeter respectively, then the actual dryness
fraction of steam will be
(a) xxx2
(b) x, + x2
Ans: a
21. 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) 0.8
(e) 1.0.
Ans: c
22. 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.
Ans: b
23. A wet vapour can be completely
specified by
(a) pressure only
(b) temperature only
(c) dryness fraction only
(d) specific volume only
(e) pressure and dryness fraction.
Ans: e
24. 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.
Ans: a
25. 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) curved line
(e) none of the above.
Ans: a
26. 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%.
Ans: a
27. 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) dry
(e) none of the above.
Ans: b
28. 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.
Ans: b
29. The dry saturated steam at very high
pressure (150-200 kg/cm2) when throttled to
atmosphere will become
(a) wet
(b) superheated
(c) remain dry saturated
(d) dry
(e) none of the above.
Ans: a
30. 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.
Ans: c
31. In a throttling process
(a) heat transfer takes place
(b) work is done by the expanding steam
(c) internal energy of steam changes
(d) all of the above
(e) none of the above.
Ans: e
32. The pressure at which latent heat of
vaporisation of water is zero, is
(a) below atmospheric pressure
(b) 1 kg/cm2
(c) 100 kg/cm2
(d) 170 kg/cm2
(e) 225.6 kg/cm2.
Ans: e
33. 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
(e) 471 kcal/kg.
Ans: a
34. The latent heat of steam with increase
of pressure
(a) remains same
(b) increases
(c) decreases
(d) behaves unpredictably
(e) none of the above.
Ans: c
35. 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
(e) none of the above.
Ans: c
36.  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
(e) it is never possible.
Ans: d
37. In an experiment to determine dryness
fraction of steam, the mass of water separated was
1.2 kg in 15 mts and the mass of steam passed out
in same time was 4.8 kg. Dryness fraction is
(a) 40%
(b) 25%
(c) 50%
(d) 80%
(e)90%.
Ans: d
38. While steam expands in turbines,
theoretically the entropy
(a) remains constant
(b) increases
(c) decreases
(d) behaves unpredictably
(e) none of the above.
Ans: a
39. Heating wet steam at constant
temperature is heating it at constant
(a) volume
(b) pressure
(c) entropy
(d) enthalpy
(e) none of the above.
Ans: b
40. Adiabatic process is
(a) essentially an isentropic process
(b) non-heat transfer process
(c) reversible process
(d) constant temperature process
(e) constant enthalpy process.
Ans: b
41. 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
(e) dryness fraction alone.
Ans: d
42. 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
(e) all properties of liquid and steam are
same.
Ans: d
43. 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
(e) boiling has ^nothing to do with vapour
pressure.
Ans: a
45.  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
(e) 75 kgm.
Ans: a
46. 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
(e) none of the above.
Ans: a
47. 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.
(e) boiler efficiency.
Ans: d
48. 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
(e) none of the above.
Ans: b
49. During polytropic process
(a) heat transfer takes place across cylinder
walls
(b) work is done
(c) steam may be wet, dry or superheated
after expansion
(d) all of the above
(e) none of the above.
Ans: d
50. Hygrometery deals with the
(a) Hygroscopic substances
(b) water vapour in air
(c) temperature of air
(d) pressure of air
(e) density measurement.
Ans: b
51. 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
(e) none of the above.
Ans: b
52. Alkaline pyrogallate is used in Orsat's
apparatus for absorption of
(a) C02
(b) CO
(c) 02
(d) N2
(e) none of the above.
Ans: c
53. An ideal regenerative cycle is
(a) equal to carnot cycle
(b) less than carnot cycle
(c) more than carnot cycle
(d) could be anything
(e) none of the above.
Ans: b
54. 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
(e) increasing number of regenerative
heaters.
Ans: a
55. Cochran boiler is a
(a) horizontal fire-tube boiler
(b) horizontal water-tube boiler
(c) veritcal water-tube boiler
(d) vertical fire tube boiler
(e) forced circulating boiler.
Ans: d
56. Lancashire 'boiler is a
(a) stationary fire tube boiler
(b) stationary water tube boiler
(c) water tube boiler with natural/forced
circulation
(d) mobile fire tube boiler
(e) none of the above.
Ans: a
57. Efficiency of a thermal cycle increases
by
(a) regeneration
(b) reheating of steam
(c) both (a) and (b)
(d) cooling of steam
(e) none of the above.
Ans: c
58. One kilowatt-hour energy is equivalent
to
(a) 1000 J
(b) 360 kJ
(c) 3600 kJ
(d) 3600 kW/sec
(e) 1000 kJ.
Ans: c
59. Which of the following gases has the
highest calorific value
(a) producer gas
(b) coal gas.
(c) water gas
(d) blast furnace gas
(e) coke oven gas.
Ans: b
60. 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
(e) none of the above.
Ans: b
61. 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) 2 kg
(e) 16/3 kg.
Ans: b
62. The diameter of Cornish boiler is of the
order of
(a) 1-2 m
(b) 1.5-2.5 m
(c) 2-3 m
(d) 2.5-3.5 m
(e) 0.5 to 1 m.
Ans: a
63. 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
(e) 9-11 m.
Ans: c
64. 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
(e) three-fifth.
Ans: a
65. Steam engine operates on
(a) carnot cycle
(b) joule cycle
(c) Stirling cycle
(d) brayton cycle
(e) none of the above.
Ans: d
66. 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
(e) none of the above.
Ans: a
67. 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
(e) none of the above.
Ans: c
68. 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
(e) none of the above types.
Ans: d
69. Lancashire boiler is of
(a) stationary<fire tube-type
(b) horizontal type
(c) natural cirulation type
(d) internally fired type
(e) all of the above.
Ans: e
70. 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
(e) none of the above.
Ans: a
71. Which of the following substance will
have same percentage in both proximate and
ultimate analysis
(a) ash
(b) volatile matter
(c) moisture
(d) hydrogen
(e) none of the above.
Ans: a
72. The number of flue tubes in Lancashire
boiler is
(a) zero
(b) one
(c) two
(d) four
(e) many.
Ans: c
73. Which of the following is a fire tube
boiler
(a) locomotive boiler
(b) Babcock and Wilcox boiler
(c) Stirling boiler.
(d) all of the above
(e) none of the above.
Ans: a
74. Which of the following is a water tube
boiler
(a) locomotive boiler
(b) Cochran boiler
(c) Cornish boiler
(d) Babcock and Wilcox boiler
(e) Lancashire boiler.
Ans: d
75. The diameter of cylindrical shell of the
Lancashire boiler is of the order of
(a) 1 tp 1.25m
(b) 1 to 1.75 m
(c) 2 to 4 m
(d) 1.75 to 2.75 m
(e) 2.25 to 4.5 m.
Ans: d
76. 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
(e) none of the above.
Ans: b
77. The biggest size of thermal power unit
operating in India is
(a) 30 MW
(b) 60 MW
(c) 100 MW
(d) 210 MW
(e) 500 MW.
Ans: e
78. Which of the following coals has the
highest calorific value
(a) anthracite coal
(b) bituminous coal
(c) lignite
(d) peat
(e) wood.
Ans: a
79. The high pressure boiler is oiie
producing steam at a pressure more than
(a) atmospheric pressure
(b) 5 kg/cm2
(c) 10 kg/cm2
(d) 40 kg/cm2
(e) 75-80 kg/cm2.
Ans: e
80. The crown of the fire box is made
hemispherical in order to
(a) give maximum space
(b) give maximum strength
(c) withstand pressure inside boiler ,
(d) resist intense heat in fire box
(e) enable easy,manufacture.
Ans: d
81. Which of the following is steam dbal
(a) non-coking bituminous coal
(b) brown coal
(c) pulverised coal
(d) coking bituminous coal
(e) none of the above.
Ans: a
82. The fire tubes in, a Coarran and Scotish
marine boiler are
(a) horizontal
(b) vertical
(c) inclined
(d) both horizontal and vertical
(e) horizontal and inclined.
Ans: a
83. 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) one-fifth
(e) two-fifth.
Ans: e
84. 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
(e) control level.
Ans: d
85. 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
(e) reciprocating pump.
Ans: e
86. The best suited coal for chain or
travelling grate stoker boiler is
(a) coking coal
(b) non coking or free burning coal
(c) pulverised coal
(d) high sulphur coal
(e) least ash content coal.
Ans: b
87. 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
(e) water is fed at atmospheric pressure.
Ans: a
88. Hard coke is produced by carborisation
of coal at
(a) atmospheric temperature
(b) 500-600°C
(c) 70O-850°C
(d) 95O-1100°C
(e) 120O-1500°C.
Ans: d
89.. Hard coke is used in
(a) cement industry
(b) thermal power plant
(c) blast furnace
(d) domestic use
(e) locomotives
Ans: c
90. 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
(e) both have two fire tubes.
Ans: d
91. 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
(e) 31 kg/cm2.
Ans: d
92. Locomotive boiler is of the following
type
(a) multitubular
(b) horizontal
(c) internally fired
(d) mobile
(e) all of the above.
Ans: e
93. The shell diameter and length of
locomotive boiler are
(a) 1.5 m, 4 m
(b) 1.5 m, 6 m
(c) 1 m, 4 m
(d) 2 m, 4 m
(e) 1.5 m, 8 m.
Ans: a
94. 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
Ans: a
95. The water tubes in a babcock and
wilcox boiler are
(a) horizontal
(b) vertical
(c) inclined
(d) horizontal and inclined
(e) vertical and inclined.
Ans: c
96. Which of the following varieties of coals
is mostly used in steam boilers
(a) non-coking bituminous coal
(b) brown coal
(c) peat
(d) coking bituminous coal
(e) none of the above.
Ans: e
97. The diameter of tubes for natural
circulation boiler as compared to controlled
circulation boilers is
(a) more
(b) less
(c) same
(d) could be more or less depending on
other factors
(e) none of the above.
Ans: a
98. A boiler in India should conform to
safety regulations of
(a) DIN
(b) BS
(c) ASTM
(d) IBR
(e) GOST.
Ans: d
99. 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
(e) control steam temperature by injecting
water.
Ans: c
100. Which of the following boilers is best
suited to meet fluctuating demands
(a) babcock and wilcox
(b) locomotive
(c) lancashire
(d) cochran
(e) comish.
Ans: b
101. 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
(e) none/of the above.
Ans: c
102. 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 mixture of water and steam
(c) feed pump is employed to supplement
natural circulation in water wall type furnace
(e) water is converted into steam in one pass
without any recirculation
(e) water is fed under high pressure and high
velocity.
Ans: b
103. 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.
Ans: e
104. 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.
Ans: d
105. 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.
Ans: c
106. 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.
Ans: d
107.  Fusible plug for boilers is made of fusible
metal containing tin, lead, and
(a) bismuth
(b) copper
(c) aluminium
(d) nickel
(e) iron.
Ans: a
108. 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.
Ans: c
109. 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
(e) heating of water takes place in stages.
Ans: c
110. 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.
Ans: e
111. 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.
Ans: a
112. Thermal efficiency of well maintained
boiler will be of the order
(a) 20%
(b) 40%
(c) 50%
(d) 75%
(e) 90%.
Ans: e
113. Thermal efficiency of a thermal power
plant is of the order of
(a) 15%
(b) 20%
(c) 30%
(d) 45%
(e ) 60%.
Ans: c
114. 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.
Ans: c
115. 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
(e) rankine cycle efficiency.
Ans: a
116. 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.
Ans: e
117. 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
(e) water is heated in a large number of
tubes.
Ans: d
118. 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.
Ans: a
119. The radius of a dished head is taken
approximately as
(a) one-fourth
(b) half
(c) one
(d) two
(e) three.
Ans: c
120. 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.
Ans: c
121. 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) radiation
(e) all of the above.
Ans: e
122. The major axis of elliptical manholes on
the shell should be provided
(a) longitudinally
(b) circumferentially
(c) on dished end
(d) anywhere
(e) vertically.
Ans: b
123. 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
(e) benson boiler.
Ans: b
124. With increase in load, radiant
superheater has
(a) drooping characteristic
(b) lihear characterisstic
(c) rising characteristic
(d) flat characteristic
(e) none of the above.
Ans: a
125. With increase in load, convection
superheater has
(a) drooping characteristic
(b) linear characterisstic
(c) rising characteristic
(d) flat characteristic
(c) none of the above.
Ans: c
126. 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.
Ans: b
127. 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
(e) none of the above.
Ans: a
128. 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.
Ans: d
129. 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
(e) above wet bulb temperature of flue
gases.
Ans: b
130. 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.
Ans: b
131. 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) stack gases should not be cooled to the
dew point
(e) none of the above.
Ans: d
132. 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.
Ans: b
133. The function of injector used in small
capacity boilers is to
(a) create vacuum
(b) inject chemical solution in feed pump
(c) pump water, similar to boiler feed
pump
(d) add make up water in the system
(e) none of the above.
Ans: c
134. 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.
Ans: b
135. 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
(e) all of the above.
Ans: c
136. 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.
Ans: e
137. 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
(e) none of the above.
Ans: c
138. Expanding steam to a very low
prseeure (high vacuum) in steam engines is
(a) desirable
(b) economical
(c) essential
(d) optional
(e) uneconomical.
Ans: e
139. In locomotives, the draught is produced
by
(a) chimney
(b) induced draft fan
(c) both combined (a) and (b)
(d) steam jet draught
(e) none of the above.
Ans: d
140. Reheating of steam under ideal
conditions takes place at constant
(a) entropy
(b) enthaply
(c) pressure
(d) temperature
(e) all of the above.
Ans: d
141. 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) outside temperature is very low
(e) more than the tallest building nearby.
Ans: c
142. 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.
Ans: b
143. Which device is used in thermal power
plants to reduce level of pollution
(a) induced draft fan
(b) smoke meter
(c) chimney
(d) precipitator
(e) pulveriser.
Ans: d
144. 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.
Ans: a
145. 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
(b) lower calorific value
(e) best analysis.
Ans: a
146. For combutsion 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.
Ans: d
147. 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
(e) none of the above.
Ans: c
148. The economiser 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.
Ans: a
149. An economiser in a boiler
(a) increases steam pressure
(b) increases steam flow
(c) decreases fuel consumption
(d) decreases steam pressure
(e) increases life of boiler.
Ans: c
150. 02 content in atmospheric air on
volume basis is
(a) 21%
(b) 23%
(d) 30%
(d) 40%
(e) 70%.
Ans: a
151. 02 content in atmospheric air on weight
basis is
(a) 21%
(b) 23%
(c) 30%
(d) 40%
(e ) 70%.
Ans: b
152. 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.
Ans: b
153. 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
(e) facilitates ash removal.
Ans: d
154. 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.
Ans: c
155. 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
(e) prevent atmospheric air leaking into
furnace.
Ans: a
156. 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.
Ans: a
157. 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) temperature at which oil is transported
(e) none of the above.
Ans: a
158. 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.
Ans: a
159. 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
(e) its type.
Ans: c
160. 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
(e) ecomomical
Ans: d
161. Sulphur in coal results in
(a) causing clinkering and slagging
(b) corroding air heaters
(c) spontaneous combustion during coal
storage
(d) facilitating ash precipitation
(e) all of the above.
Ans: e
162. 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.
Ans: a
163. Green coal, in order to be burnt, must
be
(a) heated sufficiently
(b) burnt in excess air
(c) heated to its ignition point
(d) burnt as powder
(e) burnt as lumps.
Ans: c
164. 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.
Ans: b
165. 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
(e) moisture and ash free heating value.
Ans: d
166. 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.
Ans: e
167. The safety valve on boiler drum
compared to safety valve on superheater is set at
(a) same value
(b) higher value
(c) lower value
(d) lower/higher depending on steam flow
(e) unpredicatble.
Ans: b
168. 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
(e) separate mills are required to powder
the coal.
Ans: d
169. The three "Ts" for good combustion are
(a) temperature, time, and turbulance
(b) total air, true fuel, and turbulance
(c) thorough mixing, total air, and
temperature
(d) total air, time, and temperature
(e) none of the above.
Ans: a
170.  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
(e) to minimise radiation losses.
Ans: c
171. 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
(e) none of the above.
Ans: d
172. 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
Ans: a
173. 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
(e) leakage of air.
Ans: c
174. 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.
Ans: c
175. The capacity of induced draft fan
compared to forced draft fan in a boiler is
(a) same
(b) more
(c) less
(d) less or more depending on size of boiler
(e) unpredictable.
Ans: b
176.

Nuclear Power Plants - Mechanical Engineering Multiple Choice Questions and Answers

Nuclear Power Plants -
Multiple Choice Questions and Answers

1. The efficiency of a nuclear power plant in
comparsion to a conventional thermal power plant is
(a) same
(b) more
(c) less
(d) may be less or mote depending on size
(e) unpredictable.
Ans: c
2. Isotopes of same elements have
(a) same atomic number and different masses
(b) same chemical properties but different atomic
numbers
(c) different masses and different atomic numbers
(d) different chemical properties and same atomic
numbers
(e) same chemical properties and same atomic
numbers.
Ans: b
3. Atomic number of an element in the periodic table
represents the numbers of
(a) protons in the nucleus
(b) electrons in me nucleus
(c) neutrons in the nucleus
(d) electrons in the atom
(e) neutrons in the atom.
Ans: a
4. The mass number of a substance represents the
sum of total number of
(a) protons and neutrons in an atom
(b) protons and electrons in an atom
(c) neutrons and electrons in an atom
(d) protons and neutrons in a nucleus
(e) protons and electrons in a nucleus.
Ans: d
5. Which is not identical for an atom and an isotope
(a) mass number
(b) atomic number
(c) chemical properties
(d) position in periodic table
(e) all of the above.
Ans: a
6. Amongst the following, the fissionable materials
are
(a) U233andPu239
(b) U23iandPu233
(c) U235andPu235
(d) U238andPu239
(e) U243andPu235
Ans: a
6. A nuclear unit becoming critical means
(a) it is generating power to rated capacity
(b) it is capable of generating much more than rated
capacity
(c) there is danger of nuclear spread
(d) chain reaction that causes automatic splitting
of the fuel nuclei has been established
(e) it generates no heat.
Ans: d
7. Moderator in nuclear plants is used to
(a) reduce temperature
(b) extract heat from nuclear reaction
(c) control the reaction
(d) cause collision with the fast moving neutrons to
reduce their speed
(e) moderate the radioactive pollution.
Ans: d
8. The most commonly used moderator in nuclear
plants is
(a) heavy water
(b) concrete and bricks
(c) graphite and concrete
(d) deutrium
(e) graphite.
Ans: e
9. The nuclear energy is measured as
(a) MeV
(b) curie
(c) farads
(d) MW
(e) kWhr.
Ans: a
10. The total energy released in fission of U is
(a) 5 MeV
(b) 10 MeV
(c) 199 MeV
(d) 168 MeV
(e) 11 MeV.
Ans: c
11. Breeder reactor has a conversion ratio of
(a) unity
(b) more than unity
(c) less than unity
(d) zero
(e) infinity.
Ans: b
12. Boiling water reactor employs
(a) boiler
(b) direct cycle of coolant system
(c) double circuit system of coolant cycle
(d) multi pass system
(e) single circuit system.
Ans: b
13. Fast breeder reactor uses
(a) boiler
(b) direct cycle of coolant system
(c) double circuit system of coolant cycle
(d) multi pass system
(e) single circuit system.
Ans: c
14. One gram of uranium will produce energy
equivalent to approximately
(a) 1 tonne of high grade coal
(b) 4.5 tonnes of high grade coal
(c) 10 tonnes of high grade coal
(d) 100 tonnes of high grade coal
(e) 1000 tonnes of high grade coal.
Ans: b
15.  Which of the following nuclear reactor does not
need a heat exchanger for generation of steam
(a) gas cooled
(b) liquid metal cooled
(c) pressurised water
(d) boiling water
(e) none of the above.
Ans: d
16.  The number of isotopes of hydrogen are
(a) 1
(b) 2
(c) U
(c) 3
(e) 0
Ans: c
17. The commonly used material for shielding is
(a) lead or concrete
(b) lead and tin
(c) graphite or cadmium
(d) thick galvanised sheets
(e) black carbon papers.
Ans: a
18. The main interest of shielding in nuclear reactor
is protection against
(a) X-rays
(b) infra-red rays
(c) a, P, and y rays
(d) neutrons and gamma rays
(e) electrons.
Ans: d
19. Reflector in nuclear plants is used to
(a) return the neutrons back into the core
(b) shield the radioactivity completely
(c) check polllution
(d) conserve energy
(e) is not used.
Ans: a
20. The energy required to be applied to a
radioactive nucleus for the emission of a neutron is
(a) 1 MeV
(b) 2.4 MeV
(c) 4.3 MeV
(d) 7.8 MeV
(e) 20 MeV.
Ans: d
21. Which of the following are ferrite materials
(a) U233andPu239
(b) U
(c) U238andPu239
(d) U238andTh239
(e) none of the above
Ans: b
22. Ferrite material is
(a) the most fissionable material
(b) the basic fuel for nuclear paints
(c) basic raw material for nuclear plants
(d) the material which absorbs neutrons and
undergoes spontaneous changes leading to the
formation of fissionable material
(e) none of the above.
Ans: d
23. Enriched uranium is one in which
(a) %age of U235 has been artificially in-creased
(b) %age of U has been artificially increased
(c) %age of U234 has been artificially in-creased
(d) extra energy is pumped from outside
(e) all impurities have been removed.
Ans: a
24.  Which of the following particles is the lightest
(a) nucleus
(b) electron
(c) proton
(d) meson
(e) neutron.
Ans: b
25. Which of the following is the heaviest
(a) neutron
(b) proton
(c) atom
(d) electron
(e) nucleus.
Ans: c
26.  In fast breeder reactors
(a) any type of moderator can be used
(b) graphite is used as the moderator
(c) heavy water is used as the moderator
(d) moderator may or may not be used
(e) moderator is dispensed with.
Ans: e
27. In nuclear fission each neutron that causes
fission releases
(a) no new neutron
(b) at least one new neutron
(c) one new neutron
(d) more than one new neutrons
(e) many-fold neutrons.
Ans: d
28. The breeding gain in case of thermal breeder
reactor as compared to fast breeder reactor is
(a) same
(b) lower
(c) higher
(d) unity
(e) higher/lower depending on the size of reactor.
Ans: b
29. Gas cooled reactor uses following materials as
moderator, and coolant
(a) graphite, C02
(b) graphite, air
(c) heavy water, C02
(d) lead, H2
(e) concrete, N2.
Ans: a
30. A nuclear fission produces energy of following
order in MeV
(a) 20
(b) 200
(c) 2000
(d) 20,000
(e) 2 x 105.
Ans: b
31. The process by which a heavy nucleus is
splitted into two light nuclei is known as
(a) splitting
(b) fission
(c) fusion
(d) disintegration
(e) chain reaction.
Ans: b
32. A nuclear fission is initiated when the critical
energy as compared to neutron binding energy of
the atoms is
(a) same
(b) more
(c) less
(d) there is no such criterion
(e) none of the above.
Ans: b
33. The fast breeder reactor uses the following
moderator
(a) demineralised water
(b) carbon dioxide
(c) heavy water
(d) graphite
(e) no moderator is used.
Ans: e
34. The first unclear power plant in India is located
at
(a) Kota
(b) Kalapakkam
(c) Tarapur
(d) Baraeilly
(e) Kerala.
Ans: c
35. The nuclear power plant at Tarapur has the
following reactor
(a) fast breeder
(b) pressurised water
(c) boiling water
(d) sodium graphite
(e) none of the above.
Ans: c
35. Boiling water reactor uses the following as
moderator, coolant and working fluid
(a) ordinary fluid
(b) heavy water
(c) molten lead
(d) hydrogen gas
(e) none of the above.
Ans: a
36. Ideally the neutron flux in reactor should be
(a) maximum in center and zero at side
(b) maximum at side and zero in center
(c) uniform throughout
(d) zero throughout
(e) none of the above.
Ans: c
37. Enriched uranium may contain fissionable
contents of the order of
(a) 1-99%
(b) 1-25%
(c) 1-50%
(d) 1-75%
(e) 1-90%.
Ans: a
38. U235 will undergo fission by
(a) high energy (fast) neutrons alone
(b) low energy (slow) neutrons alone
(c) either fast or slow neutrons
(d) medium energy neutrons
(e) none of the above.
Ans: c
39. U238 will undergo fission by
(a) high energy (fast) neutrons alone
(b) low energy (slow) neutrons alone
(c) either fast or slow neutrons
(d) medium energy neutrons
(e) none of the above.
Ans: a
40. A reactor capable of converting a ferrite material
into fissile isotopes is called
(a) regenerative reactor
(b) fast breeder reactor
(c) breeder reactor
(d) boiling water reactor
(e) ferrite reactor.
Ans: a
41. Hydrogen is preferred as better coolant in
comparison to C02 because former
(a) is lighter
(b) is inert
(c) has high specific heat
(d) is a good conductor
(e) all of the above.
Ans: c
42. Natural uranium is made up of
(a) 99.282% U238, 0.712% U235, 0.006% U234
(b) 99.282% U235, 0.712% U238,  0.06%' U234
(c) 99.282% U234, 0.712% U238, 0.006% U235
(d) 99.282% U235, 0.712% U234, 0.006% U238
(e) none of the above.
Ans: a
43. The risk of radioactive hazard is greatest in the
turbine with following reactor
(a) pressurised water
(b) boiling water
(c) gas cooled
(d) liquid metal cooled
(e) all of the above.
Ans: b
44. Plutonium is produced
(a) as basic raw material
(b) by neutron irradiation of Uz
(c) by neutron irradiation of throium
(d) artificially
(e) in high capacity furnace.
Ans: b
45. Electron-volt is the unit of
(a) atomic power
(b) energy
(c) voltage
(d) radio activity
(e) there is no such unit.
Ans: b
46. Pick up the wrong statement
(a) In a heterogeneous or solid-fuel reactor, the fuel
is mixed in a regular pattern within moderator.
(b) Slow or thermal neutrons have energy of the
order or 0.025 eV
(c) Fast neutrons have energies above 1000 eV
(d) Fast reactor uses moderator
(e) Most serious drawback in using water as
coolant in nuclear plants is its high vapour
pressure.
Ans: d
47. The unit of radio-activity is
(a) electron-volt
(b) electron-ampere
(c) curie
(d) MeV
(e) AMU.
Ans: c
48. Pick up the wrong statement Fast breeder
reactors
(a) operate at extremely high power densities.
(b) are liquid-metal cooled
(c) produce more fuel than they consume
(d) are unmoderated
(e) use water as coolant.
Ans: e
49. Uranium-233 is produced
(a) as basic raw material
(b) by neutron irradiation of Uz
(c) by neutron irradiation of thorium
(d) artificially
(e) in high capacity furnaces.
Ans: c
50. Plutonium-239 is produced
(a) as basic raw material
(b) by neutron irradiation of IT*
(c) by neutron irradiation of thorium
(d) artificially
(e) in high capacity furnaces.
Ans: b
51. Which of the following type of pump is used in
liquid metal cooled reactor for circulation of liquid
metal
(a) centrifugal
(b) axial
(c) reciprocation
(d) electromagnetic
(e) diaphragm.
Ans: d
52. Which of the following is the primary fuel
(a) Ulii
(b) U
(c) U238
(d) Pu:
(e) Pu
Ans: b
53. Which of the following is secondary fuel
(a) Th232andU238
(b) U233andPu239
(c) U233andPu238
Ans: c
54. A pressurised water reactor employs
pressuriser for the following application
(a) to maintain constant pressure in primary circuit
under varying load
(b) to Supply high pressure steam
(c) to increase pressure of water in primary circut
(d) to provide subcooled water at high pressure
(e) all of the above.
Ans: a
55. Which of the following can be used as a coolant
in nuclear plant
(a) light or heavy water
(b) molten lead
(c) carbon dioxide
(d) freon
(e) carbon tetrachloride.
Ans: a
56. Reactors for propulsion applications use
(a) natural uranium
(b) molten lead
(c) any form of uranium
(d) thorium
(e) plutonium.
Ans: b
57. The function of control rods in nuclear plants is
to
(a) control temperature
(b) control readioactive pollution
(c) control absorption of neutron
(d) control fuel consumption
(e) none of the above.
Ans: c
58. Breeder reactors employ liquid metal coolant
because it
(a) acts as good moderator
(b) produces maximum steam
(c) transfers heat from core at a fast rate
(d) breeds neutrons
(e) increases rate of reaction in core.
Ans: c
59. In triggering fission, which type of neutrons are
more effective
(a) fast
(b) slow
(c) in bulk
(d) static
(e) activated.
Ans: b
60. For economical operation of a nuclear plant
(a) used fuel should be reprocessed
(b) moderator should be used
(c) coolant should be employed
(d) control rods should be used
(e) reflector should be used.
Ans: a
61. The size of the reactor is said to be critical
when
(a) chain reaction can be initiated
(b) it becomes uncontrollable
(c) it explodes
(d) it produces no power
(e) it produces tremendous power.
Ans: a
62. When a reactor becomes critical, then the
production of neutrons is
(a) infinite
(b) zero
(c) exactly balanced by the loss of neutrons through
leakage
(d) initiated
(e) stopped.
Ans: c
63. In the breeder reactors the generation of new
fissionable atom is
(a) at the lower rate than the consumption
(b) at a higher rate than the constuption
(c) at an equal rate of the consumption
(d) depends on other considerations
(e) unpredictable.
Ans: b
64. The energy produced by a thermal reactor of
same size as a breeder reactor is
(a) almost same
(b) slightly more
(c) slightly less
(d) much less
(e) much more.
Ans: d
65. Reactors designed for propulsion applications
are designed for
(a) natural uranium
(b) enriched uranium
(c) pure uranium
(d) any type of uranium
(e) none of the above.
Ans: b
66. Supertheated steam is generated in following
reactor
(a) boiling water
(b) gas cooled
(c) pressurised water
(d) all of the above
(e) none of the above.
Ans: b
67. Solid- fuel for nuclear reactions may be
fabricated into various small shapes such as
(a) plates
(b) pallets
(c) pins
(d) any one of the above
(e) none of the above.
Ans: d
68. Which of the following is more appropriate for a
moderator. One which
(a) does not absorb neutrons
(b) absorbs neutrons
(c) accelerates neutrons
(d) eats up neutrons
(e) regenerates neutrons.
Ans: a
69. A fission chain reaction in uranium can be
developed by
(a) slowing down fast neutrons so that Uz fission
continues by slow motion neutrons
(b) accelerating fast neutrons
(c) absorbing all neutrons
(d) using moderator
(e) enriching U235.
Ans: a
70. In triggering fission, the following types of
neutrons are desirable
(a) fast moving
(b) slow moving
(c) critical neutrons
(d) neutrons at rest
(e) none of the above.
Ans: b
71. Effective moderators are those materials which
contain
(a) light weight atoms
(b) heavy weight atoms
(c) critical atoms
(d) zero weight atoms
(e) there is no such criterion.
Ans: a
72. In a fission process, maximum %age of energy
is released as
(a) kinetic energy of neutrons
(b) kinetic energy of fission products
(c) instantaneous release of gamma rays
(d) gradual readioactive decay of fission products
(e) none of the above.
Ans: b
73. The following present serious difficulty in
designing reactor shield
(a) alpha particles
(b) beta particles
(c) thermal neutrons
(d) fast neutrons and gamma rays
(e) none of the above.
Ans: d
74. In nuclear fission
(a) the original elements change into completely
different elements
(b) the electrons of the element change
(c) the molecules rearrange themselves to form
other molecules
(d) none of the above.
Ans: a
75. In order to have constant clain reaction to
produce a constant rate of heat output, the value of
ratio of the number of neutrons in one generation to
the number of neutrons in the immediately
preceding generation must be
(a) greater than 1.0
(b) less than 1.0
(c) equal to zero
(c) equal to 1.0
(e) equal to infinity.
Ans: d
75. Each fission of U235 produces following number
of fast neutrons per fission
(a) 1 neutron
(b) 1 — neutrons
(c) 1 - 2 neutrons
(d) 2 — neutrons
(e) infinite.
Ans: d
76. A fast breeder reactor uses following as fuel
(a) enriched uranium
(b) plutonium
(c) thorium
(d) U235
(e) natrual uranium.
Ans: d
77. A boiling water reactor uses following as fuel
(a) enriched uranium
(b) plutonium
(c) thorium
(d) U
(e) natural uranium.
Ans: a
78. A fast breeder reactor
(a) uses graphite rods as moderator
(b) has powerful moderator
(c) has no moderator
(d) uses ferrite material as moderator
(e) uses pressurised water as moderator.
Ans: c
79. Artificial radioactive isotopes find application in
(a) power generation
(b) nucleonic devices
(c) nuclear fission
(d) nuclear fusion
(e) medical field.
Ans: e
80. A fast breeder reactor uses
(a) 90% U-235
(b) U-238
(c) U-235
(d) Pu-239
(e) U-239.
Ans: a
81. Half life of a radioactive isotope corresponds to
the time required for half of the following to decay
(a) electrons
(b) protons
(c) neutrons
(d) nulceus
(e) atom.
Ans: e
82. Pressurised water reactor isdesigned
(a) for boiling pi water in the core
(b) to use liquid sodium metal as coolant
(c) to use intermediate coolant
(d) to prevent the water coolant from boiling in the
core
(e) to eliminate the coolant loop of the pressurised
water.
Ans: d
83. The coolant used in boiling water reactor is
(a) Co2
(b) pressurised water
(c) mixture of water and steam
(d) liquid metal
(e) mercury.
Ans: c
84. In boiling water reactor, moderator is
(a) coolant itself
(b) ferrite rod
(c) graphite rod
(d) liquid sodium metal
(e) blanket of thorium.
Ans: a
85. The most practical fuel for a thermo-nuclear
reactor, both from econocical and nuclear
consideration is
(a) plutonium
(b) uranium
(c) deuterium
(d) thorium
(e) lithium.
Ans: c
86. The efficiency of a nuclear power plant in
comparison to conventional and nuclear
consideration is
(a) higher cost of nuclear fuel
(b) high initial cost
(c) high heat rejection in condenser
(d) lower temperature and pressure condi-tions
(e) nuclear hazard risk.
Ans: d
87. The presence of reflector in nuclear power
plants results in
(a) increased production of neutrons
(b) complete absorption of neutrons
(c) controlled production of neutrons
(d) decreased leakage of neutrons
(e) decrease of speed of neutrons.
Ans: d
88. The fuel needed, with reflector in nuclear power
plant, in order to generate sufficient neutrons to
sustain a chain reaction, would be
(a) more
(b) less
(c) same
(d) zero
(e) negative, i.e. fuel would be generated.
Ans: b

I.C. Engines Questions and Answers

I.C. Engines Questions and Answers

1. The working cycle in case of four stroke engine
is completed in following number of revolutions of
crankshaft
(a) 1/2
(b) 1
(c) 2
(d) 4
(e) 8.
Ans: c
2. In a diesel engine, the fuel is ignited by
(a) spark
(b) injected fuel
(c) heat resulting from compressing air that is
supplied for combustion
(d) ignition
(e) combustion chamber.
Ans: c
3. Scavenging air in diesel engine means
(a) air used for combustion sent under pres-sure
(b) forced air for cooling cylinder
(c) burnt air containing products of combustion
(d) air used for forcing burnt gases out of engine's
cylinder during the exhaust period
(e) air fuel mixture.
Ans: d
4. Supercharging is the process of
(a) supplying the intake of an engine with air at a
density greater than the density of the surrounding
atmosphere
(b) providing forced cooling air
(c) injecting excess fuel for raising more load
(d) supplying compressed air to remove combustion
products fully
(e) raising exhaust pressure.
Ans: a
5. Does the supply of scavenging air at a density
greater than that of atmosphere mean engine is
supercharged ?
(a) yes
(b) no
(c) to some extent
(d) unpredictable
(e) depends on other factors.
Ans: b
6. The ratio of indicated thermal efficiency to the
corresponding air standard cycle efficiency is called
(a) net efficiency
(b) efficiency ratio
(c) relative efficiency
(d) overall efficiency
(e) cycle efficiency.
Ans: c
7. Compression ratio of LC. engines is
(a) the ratio of volumes of air in cylinder before
compression stroke and after compression stroke
(b) volume displaced by piston per stroke and
clearance volume in cylinder
(c) ratio of pressure after compression and before
compression
(d) swept volume/cylinder volume
(e) cylinder volume/swept volume.
Ans: a
8. The air standard efficiency of an Otto cycle
compared to diesel cycle for the given compression
ratio is
(a) same
(b) less
(c) more
(d) more or less depending on power rating
(e) unpredictable.
Ans: c
9. The calorific value of gaseous fuels is expressed
in terms of
(a) kcal
(b) kcal/kg
(c) kcal/m2
(d) kcal/n?
(e) all of the above.
Ans: d
11. If the intake air temperature of I.C. engine
increases, its efficiency will
(a) increase
(b) decrease
(c) remain same
(d) unpredictable
(e) depend on other factors.
Ans: b
12. All heat engines utilize
(a) low heat value of oil
(b) high heat value of oil
(c) net claorific value of oil
(d) calorific value of fuel
(e) all of the above.
Ans: a
13. An engine indicator is used to determine the
following
(a) speed
(b) temperature
(c) volume of cylinder
(d) m.e.p. and I.H.P.
(e) BHP.
Ans: d
14. Fuel oil consumption guarantees for I .C. engine
are usually based on
(a) low heat value of oil
(b) high heat value of oil
(c) net calorific value of oil
(d) calorific value of fuel
(e) all of the above.
Ans: b
17. If the compression ratio of an engine working on
Otto cycle is increased from 5 to 7, the %age
increase in efficiency will be
(a) 2%
(b) 4%
(c) 8%
(d) 14%
(e) 27%.
Ans: d
18. In case of gas turbines, the gaseous fuel
consumption guarantees are based on
(a) high heat value
(b) low heat value
(c) net calorific value
(d) middle heat value
(e) calorific value.
Ans: b
19. In a typical medium speed 4-stroke cycle diesel
engine the inlet valve
(a) opens at 20° before top dead center and closes
at 35° after the bottom dead center
(b) opens at top dead center and closes at bottom
dead center
(c) opens at 10° after top dead center and closes
20° before the bottom dead center
(d) may open or close anywhere
(e) remains open for 200°.
Ans: a
20. The pressure and temperature at the end of
compression stroke in a petrol engine are of the
order of
(a) 4 - 6 kg/cm2 and 200 - 250°C
(b) 6 - 12 kg/cm2 and 250 - 350°C
(c) 12 - 20 kg/cm2 and 350 - 450°C
(d) 20 - 30 kg/cm2 and 450 - 500°C
(e) 30 - 40 kg/cm2 and 500 - 700°C.
Ans: b
21. The pressure at the end of compression in the
case of diesel engine is of the order of
(a) 6 kg/cm
(b) 12kg/cmz
(c) 20 kg/cmz
(d) 27.5 kg/cmz
(e) 35 kg/cm
Ans: e
22. The maximum temperature in the I.C. engine
cylinder is of the order of
(a) 500- 1000°C
(b) 1000- 1500°C
(c) 1500-2000°C
(d) 2000-2500°C
(e) 2500-3000°C
Ans: d
23. The thermal efficiecny of a diesel cycle having
fixed compression ratio, with increase in cut-off
ratio will
(a) increase
(b) decrease
(c) be independent
(d) may increase or decrease depending on other
factors
(e) none of the above.
Ans: b
24. Pick up the wrong statement
(a) 2-stroke engine can run in any direction
(b) In 4-stroke engine, a power stroke is obtained in
4-strokes
(c) thermal efficiency of 4-stroke engine is more
due to positive scavenging
(d) petrol engines work on otto cycle
(e) petrol engines occupy more space than diesel
engines for same power output.
Ans: e
25. Combustion in compression ignition engines is
(a) homogeneous
(b) heterogeneous
(c) both (a) and (b)
(d) laminar
(e) turbulent.
Ans: b
26. The fuel in diesel engine is normally injected at
pressure of
(a) 5-10 kg/cm2
(b) 20-25 kg/cm2
(c) 60-80 kg/cm2
(d) 90-130 kg/cm2
(e) 150-250 kg/cm2
Ans: d
27. The specific fuel consumption per BHP hour for
diesel engine is approximately
(a) 0.15 kg
(b) 0.2 kg
(c) 0.25 kg
(d) 0.3 kg
(e) 0.35 kg.
Ans: b
28. The temperature of interior surface of cylinder
wall in normal operation is not allowed to exceed
(a) 80°C
(b) 120°C
(c) 180°C
(d) 240°C
(e) 320°C.
Ans: c
30. Crankcase explosion in I.C. engines usuall
occurs as
(a) first a mild explosion followed by a bi explosion
(b) first a big explosion followed by a mil explosion
(c) both mild and big explosions occi simultaneously
(d) never occurs
(e) unpredictable.
Ans: a
31. Compression loss in I.C engines occurs duto
(a) leaking piston rings
(b) use of thick head gasket
(c) clogged air-inlet slots
(d) increase in clearance volume caused b bearing-
bushing wear
(e) all of the above.
Ans: e
32. The specific fuel consumption per BH hour for a
petrol engine is approximately
(a) 0.15 kg
(b) 0.2 kg
(c) 0.25 kg
(d) 0.3kg
(e) 0.35 kg.
Ans: c
33. The air requirement of a petrol engine during
starting compared to theoretical airequired for
complete combustion is
(a) more
(b) loss
(c) same
(d) may be more or less depending on engine
capacity
(e) unpredictable.
Ans: b
34. The inlet value of a four stroke cycle I.C engine
remains open for nearly
(a) 180°
(b) 125°
(c) 235°
(d) 200°
(e) 275°.
Ans: c
35. Which of the following is not an interns
combustion engine
(a) 2-stroke petrol engine
(b) 4-stroke petrol engine
(c) diesel engine
(d) gas turbine
(e) steam turbine.
Ans: e
36. Pick up the false statement
(a) Thermal efficiency of diesel engine i about 34%
(b) Theoretically correct mixture of air am petrol is
approximately 15 : 1
(c) High speed compression engines operate on
dual combustion cycle
(d) Diesel engines are compression ignition engines
(e) S.I. engines are quality-governed engines.
Ans: e
37. If one cylinder of a diesel engine receives more
fuel than the others, then for that cylinder the
(a) exhaust will be smoky
(b) piston rings would stick into piston grooves
(c) exhaust temperature will be high
(d) engine starts overheating
(e) scavenging occurs.
Ans: e
38. The output of a diesel engine can be increased
without increasing the engine revolution or size in
following way
(a) feeding more fuel
(b) increasing flywheel size
(c) heating incoming air
(d) scavenging
(e) supercharging.
Ans: e
39. It the temperature of intake air in IC engines is
lowered, then its efficiency will
(a) increase
(b) decrease
(c) remain same
(d) increase upto certain limit and then decrease
(e) decrease upto certain limit and then in-crease.
Ans: a
40. In a typical medium speed 4-stroke cycle diesel
engine
(a) compression starts at 35° after bottom dead
center and ends at top dead center
(b) compression starts at bottom dead center and
ends at top dead center
(c) compression starts at 10° before bottom dead
center and, ends just before top dead center
(d) may start and end anywhere
(e) none of the above.
Ans: a
41. For the same compression ratio
(a) Otto cycle is more efficient than the Diesel
(b) Diesel cycle is more efficient'than Otto
(c) both Otto and Diesel cycles are, equally efficient
(d) compression ratio has nothing to do with
efficiency
(e) which is more efficient would depend on engine
capacity.
Ans: a
42.  The precess of breaking up or a lipuid into fine
droplets by spraying is called
(a) vaporisation
(b) carburetion
(c) ionisation
(d) injection
(e) atomisation.
Ans: e
43. As a result of detonation in an I.C. engine,
following parameter attains very high value
(a) peak pressure
(b) rate of rise of pressure
(c) rate of rise of temperature
(d) peak temperature
(e) rate of rise of horse-power.
Ans: b
44. Which of the following statements is correct?
(a) All the irreversible engines have same
efficiency
(b) All the reversible engines have same
efficiency
(c) Both Rankine and Caront cycles have same
efficiency between same temperature limits
(d) All reversible engines working between same
temperature limits have same-efficiency
(e) Between same temperature limits, both petrol
and diesel engines have same efficiency.
Ans: d
45. Most high speed compression engines operate
on
(a) Diesel cycle
(b) Otto cycle
(c) Dual combustion cycle
(d) Special type of air cycle
(e) Carnot cycle.
Ans: c
48. The accunmulation of carbon in a cylinder
results in increase of
(a) clearance volume
(b) volumetric efficiency
(c) ignition time
(d) effective compression ratio
(e) valve travel time.
Ans: d
49. Which of the following medium is compressed in
a Diesel engine cylinder
(a) air aione
(b) air and fuel
(c) air and lub oil
(d) fuel alone
(e) air, fuel and lub oil.
Ans: a
54. The air-fuel ratio of the petrol engine is
controlled by
(a) fuel pump
(b) governor
(c) injector
(d) carburettor
(e) scavenging.
Ans: d
55. In a typical medium speed, 4-stroke cycle diesel
engine
(a) fuelinjection starts at 10° before to dead center
and ends at 20° after tor dead center
(b) fuel injection starts at top dead center and ends
at 20° after top dead center
(c) fuel injection starts at just before top dead
center and ends just after top deac center
(d) may start and end anywhere
(e) none of the above.
Ans: a
56. Diesel fuel, compared to petrol is
(a) less difficult to ignite
(b) just about the same difficult to ignite
(c) more difficult to ignite
(d) highly ignitable
(e) none of the above.
Ans: c
57. In diesel engine the diesel fuel injected into
cylinder would burn instantly at about compressed
air temperature of
(a) 250°C
(b) 500°C
(c) 1000°C
(d) 150CPC
(e) 2000°C.
Ans: c
58. When crude oil is heated, then which of the
following hydrocarbon is given off first.
(a) kerosene
(b) gasoline
(c) paraffin
(d) diesel
(e) natural gas.
Ans: e
59. The rating of a diesel engine, with increase in
airintlet temperature, will
(a) increase linearly
(b) decrease linearly
(c) increase parabolically
(d) decrease parabolically
(e) first decrease linearly and then increase
parabolically.
Ans: b
60. A 75 cc engine has following parameter as 75 cc
(a) fuel tank capacity
(b) lub oil capacity
(c) swept volume
(d) cylinder volume
(e) clearance volume.
Ans: c
61. A heat engine utilises the
(a) calorific value of oil
(b) low heat value of
(c) high heat value of oil
(d) mean heat value of oil
(e) all of the above.
Ans: c
62. Gaseous-fuel guarantees are based on
(a) calorific value of oil
(b) low heat value of oil
(c) high heat value of oil
(d) mean heat value of oil
(e) all of the above.
Ans: b
63. Fuel consumption of diesef engines is not
guaranteed at one quarter load because at such low
loads
(a) the friction is high
(b) the friction is unpredictable
(c) the small difference in cooling water
temperature or in internal friction has a
disproportionate effect
(d) the engine is rarely operated
(e) none of the above.
Ans: c
64. Polymerisation is a chemical process in
which molecules of a compound become
(a) larger
(b) slowed down
(c) smaller
(d) liquid
(e) gaseous.
Ans: a
65. The term scavenging is generally associated
with
(a) 2-stroke cycle engines
(b) 4-stroke cycle engines
(c) aeroplane engines
(d) diesel engines
(e) high efficiency engines.
Ans: e
66. In diesel engine, the compression ratio in
comparison to expansion ratio is
(a) same
(b) less
(G) more
(d) variable
(e) more/less depending on engine capacity.
Ans: c
67. The cam shaft of a four stroke I.C. engine
running at 1500 rmp will run at
(a) 1500 rpm
(b) 750 rpm
(c) 3000 rpm
(d) any value independent of engine speed
(e) none of the above.
Ans: b
68. Engine pistons 'are usually made of aluminium
alloy because it
(a) is lighter
(b) wears less
(c) absorbs shocks
(d) is stronger
(e) does not react with fuel and lub oil.
Ans: a
69. Most high speed compression engines operate
on
(a) Otto cycle
(b) Diesel cycle
(c) Dual cycle
(d) Carnot cycle
(e) Two stroke cycle.
Ans: c
70. The specific fuel consumption of a petrol engine
compared to diesel engine of same H.P. is
(a) same
(b) more
(c) less
(d) less or more depending on operating conditions
(e) unpredictable.
Ans: b
71. A diesel engine as compared to petrol engine
(both running ar rated load) is
(a) more efficient
(b) less efficient
(c) equally efficient
(d) unperdictable
(e) other factors will decide it.
Ans: a
72.  The size of inlet valve of.an engine in
comparison to exhaust valve is
(a) more
(b) less
(c) same
(d) more/less depending on capacity of engine
(e) varies from design to design.
Ans: b
74. In a cycle, the spark lasts roughly for
(a) 1 sec
(b) 0.1 sec
(c) 0.01 sec
(d) 0.001 sec
(e) 0.0001 sec.
Ans: d
75. Which of the following is false statement :
Excess quantities of sulphur in diesel fuel are
Objectionable because it may cause the following
(a) piston ring and cylinder wear
(b) formation of hard coating on piston skirts
(c) oil sludge in the engine crank case
(d) detonation
(e) forms corrosive acids.
Ans: d
76. Which of the following is false statement. Some
of the methods used to reduce diesel smoke are as
follows
(a) using additives in the fuel
(b) engine derating i.e. reducing the maxi-mum flow
of fuel
(c) increasing the compression ratio
(d) adherence to proper fuel specification
(e) avoidance of overloading.
Ans: c
77. The fuel air ratio in a petrol engine fitted with
suction carburettor, operating with dirty air filter as
compared to clean filter will be
(a) higher
(b) lower
(c) remain unaffected
(d) unpredictable
(e) none of the above.
Ans: a
78. Pick up the wrong statement about
supercharging
(a) supercharging reduces knocking in diesel
engines
(b) there can be limited supercharging in petrol
engines because of detonation
(c) supercharging at high altitudes is essential
(d) supercharging results in fuel economy
(e) supercharging is essential in aircraft engines.
Ans: d
79. The actual volume of fresh charge admitted in
4-stroke petrol engine is
(a) equal to stroke volume
(b) equal to stroke volume and clearance volume
(c) less than stroke volume
(d) more than stroke volume
(e) more than cylinder volume.
Ans: c
80. The magneto in an automobile is basically
(c) transformer
(b) d.c. generator
(c) capacitor
(d) magnetic circuit
(e) a.c. generator.
Ans: b
81. The reason for supercharging in any engine is to
(a) increase efficiency
(b) increase power
(c) reduce weight and bulk for a given out-put
(d) effect fuel economy
(e) none of the above.
Ans: c
82. The operation of forcing additional air under
pressure in the engine cylinder is known as
(a) scavenging
(b) turbulence
(c) supercharging
(d) pre-ignition
(e) dissociation and carburretion of fuel.
Ans: c
83. Supercharging is essential in
(a) diesel engines
(b) gas turbines
(c) petrol engines
(d) aircraft engines
(e) marine engines.
Ans: d
84. The minimum cranking speed in case of petrol
engine is about
(a) half the operating speed
(b) one-fourth of operating speed
(c) 250-300 rpm
(d) 60-80 rpm
(e) 10-20 rpm
Ans: d
85. In a typical medium speed 4 stroke cycle diesel
engine
(a) exhaust valve opens at 35° before bot-tom dead
center and closes at 20° after top dead center
(b) exhaust valve opens at bottom 'dead center and
closes at top dead center
(c) exhaust valve opens just after bottom dead
center and closes just before top dead center
(d) may open and close anywhere
(e) none of the above is true.
Ans: a
86. Flash point of fuel oil is
(a) minimum temperature to which1 oil is heated
in order to give off inflammable vapours in sufficient
quantity to ignite momentarily when brought in
contact with a flame
(b) temperature at which it solidifies or congeals
(c) temperature at which it catches fire without
external aid
(d) indicated by 90% distillation temperature, i.e.
when 90% of sample oil has distilled off
(e) none of the above.
Ans: a
87. The mean effective pressure obtained from
engine indicator indicates the
(a) maximum pressure developed
(b) minimum pressure
(c) instantaneous pressure at any instant
(d) exhaust pressure
(e) average pressure.
Ans: e
88. For the same power developed in I.C. engines,
the cheaper system is
(a) naturally aspirated
(b) supercharged
(c) centrifugal pump
(d) turbo charger
(e) none of the above.
Ans: b
89. Installation of supercharger on a four-cycle
diesel engine can result in the following percentage
increase in power
(a) upto 25%
(b) upto 35%
(c) upto 50%
(d) upto 75%
(e) upto 100%.
Ans: e
90. Scavenging is usually done to increase
(a) thermal efficiency
(b) speed
(c) power output
(d) fuel consumption
(e) all of the above.
Ans: c
91. Which of the following is the lightest and most
volatile liquid fuel
(a) diesel
(b) kerosene
(c) fuel oil
(d) gasoline
(e) lub oil.
Ans: d
92. The theoretically correct air fuel ratio for petrol
engine is of the order of
(a) 6 : 1
(b) 9 : 1
(c) 12 : 1
(d) 15 : 1
(e) 20 : 1.
Ans: d
93. Air fuel ratio for idling speed of a petrol engine is
approximately
(a) 1 : 1
(b) 5 : 1
(c) 10:1
(d) 15 : 1
(e) 20 : 1.
Ans: c
94. Air fuel ratio at which a petrol engine can not
work is
(a) 8 : 1
(b) 10 : 1
(c) 15 : 1
(d) 20 : 1 and less
(e) will work at all ratios.
Ans: d
95. For maximum power generation, the air fuel
ratio for a petrol engine for vehicles, is of the order
of
(a) 9 : 1
(b) 12 : 1
(c) 15 : 1
(d) 18 : 1
(e) 20: 1.
Ans: b
96. The following volume of air is required for
consuming 1 liter of fuel by a four stroke engine
(a) 1 m3
(b) 5 m3
(c) 5-6 m3
(d) 9-10 m3
(e) 15-18 m3.
Ans: d
97. Pour point of fuel oil is the
(a) minimum temperature to which oil is heated in
order to give off inflammable vapours in sufficient
quantity to ignite momentarily when brought in
contact with a flame
(b) temperature at which it solidifies or congeals
(c) it catches fire without external aid
(d) indicated by 90% distillation temperature i.e.,
when 90% of sample oil has distilled off
(e) temperature at which it flows easily.
Ans: b
98. A 5 BHP engine running at full load would
consume diesel of the order of
(a) 0.3 kg/hr
(b) 1 kg/hr
(c) 3 kg/hr
(d) 5 kg/hr
(e) 10 kg/hr.
Ans: b
99. Diesel engine can work on very lean air fuel
ratio of the order of 30 : 1. A petrol engine can also
work on such a lean ratio provided
(a) it is properly designed
(b) best quality fuel is used
(c) can not work as it is impossible
(d) flywheel size is proper
(e) engine cooling is stopped.
Ans: c
100. A diesel engine has
(a) 1 valve
(b) 2 valves
(b) 3 valves
(d) 4 valves
(e) no valve.
Ans: c
101. A hmh flame speed is obtained in diesel engine
when air fuel ratio is
(a) uniform throughout the mixture
(b) chemically correct mixture
(c) about 3-5% rich mixture
(d) about 10% rich mixture
(e) about 10% lean mixture.
Ans: d
102. The knock in diesel engine occurs due to
(a) instantaneous and rapid burning of the first part
of the charge
(b) instantaneous atuo iginition of last part of charge
(c) delayed burning of the first part of the charge
(d) reduction of delay period
(e) all ot the above.
Ans: a
103. The air-fuel ratio in petrol engines-is
controlled by
(a) controlling valve opening/closing
(b) governing
(c) injection
(d) carburettion
(e) scavenging and supercharging.
Ans: d
104. Volatility of diesel fuel oil is
(a) minimum temperature to which oil is heated in
order to give off inflammable vapours in sufficient
quantity to ignite momentarily when brought in
contact with a flame
(b) temperature at which it solidifies or congeals
(c) it catches fire without external aid
(d) indicated by 90% distillation temperature, i.e.,
when 90% of sample oil has distilled off
(e) temperature at which it flows easily.
Ans: d
105. Which is more viscous lub oil
(a) SEA 30
(b) SAE 4£
(c) SAE 50
(d) SAE 70
(e) SAE 80.
Ans: e
106. In the opposed piston diesel engine, the
combustion chamber is located
(a) above the piston (/;) below the piston
(c) between the pistons
(d) any when
(e) there is no such criterion.
Ans: c
107. A stoichiometric air-fuel ratio is
(a) chemically correct mixture
(b) lean mixture
(c) rich mixture for idling
(d) rich mixture for over loads
(e) the ratio used at full rated parameters.
Ans: a
108. In a naturally aspirated diesel engine, the air is
supplied by
(a) a supercharger
(b) a centrifugal blower
(c) a vacuum chamber
(d) an injection tube
(e) forced chamber
Ans: c
109. In loop scavenging, the top of the piston is
(a) flat
(b) contoured
(c) slanted
(d) depressed
(e) convex shaped.
Ans: b
110. In the crankcase method of scavenging, the air
pressure is produced by
(a) supercharger
(b) centrifugal pump
(c) natural aspirator
(d) movement of engine piston
(e) reciprocating pump.
Ans: d
111. In order to prevent formation of carbon on the
injector, the temperature of nozzle tip should be
(a) less than 100°C
(b) between 100-250°C
(c) between 250 - 300°C
(d) between 400 - 500°C
(e) between 500 - 1000°C.
11 The thermal efficiency of a petrol engine of two
stroke with crank case scavenging as compared to
four stroke petrol engine with same comperssion
ratio will be
(a) higher
(b) lower
(c) same
(d) depends on size of engine
(e) unpredictable.
113. Ignition quailty of petrol is expressed by
(a) octane number
(b) cetane number
(c) calorific value
(d) self ignition temperature
(e) distillation temperature.
114. Petrol is distilled at a temperature in range of
(a) 30 - 65°C
(b) 65 - 220°C
(c) 220-350°C
(d) 350-450°C
(e) 450-550°C.
115. Kerosene is distilled at
(a) 30 - 65°C
(b) 65 - 220°C
(c) 220 - 350°C
(d) 350 - 450°C
(e) 450-550°C.
116. Self-ignition temperature of petrol is of the
order of
(a) 150°C
(b) 240°C
(c) 370°C
(d) 450°C
(e) more than 500°C.
117. Iso-oct ,ne
(a) has octane number of 0
(b) has octane number of 50
(c) has octane number of 100
(d) is an index of detonation quality
(e) is an index of knocking quality.
118. Octane number is determined by comparing
the performance of the petrol with the following
hydrocarbons
(a) iso-octane
(b) mixture of normal heptane and iso-oc-tane
(c) alpha methyl napthalene
(d) mixture of methane and ethane
(e) mixture of paraffins and aromatics.
119. Cetane
(a) has zero cetane number
(b) has 100 cetane number
(c) helps detonation
(d) is a straight chain paraffin
(e) determines the efficiency of an I.C. engine.
120. Ethyl fluid is used
(a) to increase the octane rating of the fuel
(b) to increase the cetane rating of the fuel
(c) as a defrosting agent
(d) as a superior type of fluid compared to others
(e) to improve lubricating quality of fuel.
121. The self-ignition temperature of diesel oil
compared to petrol is
(a) higher
(b) lower
(c) same
(d) depends on quality of fuel
(e) unpredictable?
112. Normal heptane
(a) accelerates auto-ignition
(b) helps to resist auto-ignition
(c) does not affect auto-ignition
(d) has no relation with auto-ighition
(e) retards auto-ignition.
123. Cetane number is determined by comparing
the performance of diesel oil with the following
hydrocarbons
(a) cetane
(b) mixture of cetane and alphamethyl napthalene
(c) ethylene dibromide
(d) mixture of aldehydes and ketones
(e) mixture of cetane with tetra-ethyl lead
124. Which is correct statement about reaction time
for autoignition of fuel and the fuel air ratio
(a) lean mixture has high reaction time
(b) rich mixture has high reaction time
(c) chemically correct mixture has mini-mum
reaction time
(d) all of the above.
(e) non of the above.
125. Violent sound pulsations within the cylinder of
an I.C. engine are caused due to
(a) heavy turbulence
(b) improved scavenging
(c) heavy supercharging
(d) detonation
(e) preignition.
126. Auto-ignition temperature is
(a) minimum temperature to which oil is heated in
order to give off inflammable vapours in sufficient
quantity to ignite momentarily when brought in
contact with a flame
(b) temperature at which it solidifies or congeals
(c) that at which it catches fire without external aid
(d) indicated by 90% distillation temperature, i.e.,
when 90% of sample oil has distilled off
(e) indicated by 50% distillation temperature.
127. Ignition lag is
(a) the time taken by fuel after injection (before top
dead center) to reach upto auto-ignition
temperature
(b) time before actual fuel injection and the pump
plunger starts to pump fuel
(c) time corresponding to actual injection and top
dead center
(d) time corresopnding to actual ingition and top
dead center
(e) none of the above.
128. The spark plug gap is normally maintained at
(a) 0.1 to 0.2 mm
(b) 0.2 to 0.4 mm
(c) 0.45 to 0.6 mm
(d) 0.6 to 0.8 mm
(e) 0.8 to 1 mm.
129. The function of a fuel pump in a petrol pump is
to
(a) inject fuel in cylinder
(b) supply fuel when carburettor fails
(c) pump fuel so that it reaches carburettor (to
improve thermal efficiency)
(d) does not exist.
130. The delay period in petrol engine is of the order
of
(a) 0.001 sec
(b) 0.002 see
(c) 0.01 sec
(d) 0.05 sec
(e) 0.1 sec.
131. Detonation is caused by the following unstable
compounds
(a) peroxides, aldehydes and ketones
(b) peroxides, aldehydes, oxides and sul-phides
(c) aldehydes, oxides and ketones
(d) ketones and sulphur compounds
(e) none of the above.
13 If overhead clearance is less, then the following
type of engine should be selected
(a) V-type
(b) In-line
(c) Vertical
(d) Horizontal
(e) Radial.
133. Which is false statement about advantages of
V-type engine
(a) compact design requiring lesser space
(b) improved distribution of air to cylinder
(c) casting less liable to distortion
(d) reduced torsional vibration because of shorter
crankshaft
(e) less overhead clearance.
134. The pistons are usually given a coating such
as tin plating in order to
(a) reduce weight
(b) conduct heat efficiently
(c) reduce possibility of scoring
(d) reduce friction
(e) increase lubrication effect.
135. Piston rings are usually made of
(a) cast iron
(b) aluminium
(c) phosphor bronze
(d) babbitt
(e) carbon steel.
136. Piston rings are plated with
chromium,cadmium or phosphate in order to
(a) reduce cost
(b) improve surface finish
(c) prevent clogging
(d) reduce wear and eliminate scuffing
(e) improve heat transfer.
137. The top piston ring nearer to the piston crown
is known as
(a) compression ring
(b) oil ring
(c) scrapper ring
(d) groove ring
(e) leading ring.
138. In order to prevent knock in the S.I. engines,
the charge away from the spark plug should have
(a) low temperature
(b) low density
(c) long ignition delay
(d) rich mixture
(e) all of the above.
139. Diesel engines have low specific fuel
consumption compared to petrol engine. This
statement is
(a) not true
(b) true at full load
(c) true at part load
(d) true at both part and full load
(e) there could not be any such criterion.
140. To reduce the possibility of knock in the C.I.
engines, the first elements of fuel and air should
have
(a) high temperature
(b) high density
(c) short delay
(d) reactive mixture
(e) all of the above.
141. The detonation tendency in petrol engines for
specified conditions of fuel rating, compression
ratio, speed etc. can be con-trolled by having
(a) smaller cylinder bore
(b) bigger cylinder bore
(c) medium cylinder bare
(d) cylinder bore could be anything as it does not
control detonation
(e) proper stroke legth.
142. According to Recardo's theory, detonation
occurs due to
(a) instantaneous auto-ignition of last part of charge
to be burnt
(b) improper mixing of air and fuel
(c) improper combustion
(d) self ignition temperature has nothing to do
with detonation
(e) none of the above.
143. A fuel will detonate less if it has
(a) higher self ignition temperature
(b) lower self ignition temperature
(c) proper self ignition temperature
(d) self ingition temperature has nothing to do with
detonation
(e) none of the above.
144. The knocking in diesel engines for given fuel,
will be
(a) enhanced by increasing compression ratio
(b) enhanced by decreasing compression ratio
(c) unaflected by compression ratio
(d) first enhanced by increasig compression ratio
upto a limit beyond which it will be suppressed
(e) dependent on other factors.
145. The ignition of charge by some hot surface in
the engine cylinder before operation of spark plug is
known as
(a) auto ignition
(b) preignition /
(c) retarded ignition
(d) accelerated ignition
(e) detonation.
146. Injection lag is
(a) the time taken by fuel after injection (before top
dead center) to reach upto auto-ignition
temperature
(b) time before actual fuel injection and the pump
pluger starts to pump fuel
(c) time corresponding to actual injection and top
dead center
(d) time corresponding to actual ignition and top
dead center
(e) none of the above.
147. Ignition quality of diesel-fuel oil is expressed
by an index called
(a) octane number
(b) cetane number
(c) calorific value
(d) carbon content
(e) ignition temperature.
148. For best results of efficient combustion, high
speed diesel engines need an approximate cetane
number of
(a) 100
(b) 10
(c) 50
(d) 5
(e) 1.
149. Calorific value of diesel oil is of the order of
(a) 3000 kcal/kg
(b) 5000 kcal/kg
(c) 7500 kcal/kg
(d) 10000 kcal/kg
(e) 15000 kcal/kg.
150. Carbon residue in diesel oil should not be more
than
(a) 1%
(b) 0.5%
(c) 0.1%
(d) 0.01%
(e) 0.001%.
151. The most popular firing order in case of four
cylinder in-line I.C. engine is
(a) 1-2-3-4
(b) 1-3-2-4
(c) 1-4-2-3
(d) 1-2-4-3
(e) 1-3-4-
15 The compression ratio of motor cars is
(a) 5
(b) 1
(c) 10
(d) 13
(e) 16.
153. The specific gravity of diesel oil Is
(a) 1
(b) 0.7
(c) 0.85
(d) 0.5
(e) 1.25.
154. Freezing temperature of petrol is usually
(a) 0°C
(b) - 10°C
(c) 10°C
(d) less than - 30°C
(e) less than - 273°C.
155. The specific gravity of petrol is about
(a) 0.65
(b) 0.75
(c) 0.85
(d) 0.95
(e) 1.1.
156. Pick up the correct statement. Detonation can
be controlled by
(a) varying compression ratio
(b) using lian mixture
(c) retarding the spark timing
(d) reducing the r.p.m.
(e) increasing inlet pressure.
157. The efficiency of I.C. engines normally is of the
order of
(a) 15-20%
(b) 20-25%
(c) 25-30%
(d) 30-35%
(e) 35-50%.
158. The firing order in a six stroke I.C. engine is
(a) 1-3-6-5-2-4
(b) 1-4-2-5-6-3
(c) 1-6-2-5-4-3
(d) 1-5-2-6-3-4
(e) 1-5-3-4-2-6.
159. Sulphur content in diesel oil should not be more
than
(a) 10%
(b) 5%
(c) 1%
(d) 0.1%
(e) 0.01%.
160. The m.e.p. of a diesel cycle having fixed
compression ratio with increase in cut-off will
(a) increase
(b) decreae
(c) be unaffected
(d) depend on other factors
(e) unpredictable.
161. The ash content in diesel oil should bot be
more than
(a) 1%
(b) 5%
(c) 0.1%
(d) 0.01%
(e) 0.001%.
16 The pour point of diesel oil must be
(a) lower than the coldest atmospheric temperature
at which oil is to be pumped
(b) higher than above
(c) has no such relation
(d) more than 100°C
(e) none of the above.
163. High carbon content in diesel oil used for diesel
engine leads to
(a) production of highly corrosive gases corroding
the cylinder walls and exhaust system
(b) excessive engine wear
(c) damaging of both the storage tank and the
engine
(d) deposition on engine parts
(e) none of the above.
164. Exhaust pipes of engines are covered with
insulating marterial in order to
(a) keep the exhaust pipes warm
(b) reduce formation of condenstae
(c) reduce heat transfer to the engine room
(d) increase engine efficiency
(e) conserve heat.
165. Ignition timing of a multicylider petrol engine
can be adjusted by
(a) rotating the crank
(b) adjusting the spark plug gap
(c) adjusting ignition coil position
(d) rotating the distributor
(e) delaying the spark by increasing capacitor in
ignition circuit.
166. Fuel consumption with increase in back
pressure will
(a) increase
(b) decrease
(c) remain unaffected
(d) depend on other factors
(e) none of the above.
167. The cooling water requirement for diesel
engine is of the order of
(a) 0.2 to 1.0 liter per minute per h.p.
(b) 1 to 3 liters per minute per h.p.
(c) 5 to 10 liters per minute per h.p
(d) 10 to 20 liters per minute per h.p.
(e) 20-30 liters per minute per h.p.
168. A 4-stroke diesel engine needs about following
amount of air
(a) 75 cc per min. per h.p.
(b) 750 cc per min. per h.p.
(c) 7500 cc per min. per h.p.
(d) 75000 cc per min. per h.p.
(e) 750000 cc per min. per h.p.
169. Leakage past the piston rings and valve seats
in I.C. engines with increase in speed
(a) increases .
(b) decreases
(c) remains same
(d) unpredictable
(e) none of the above.
170. The heat wasted in diesel engine is of the
order of
(a) 80%
(b) 65%
(c) 50%
(d) 35%
(e ) 25%.
171. With increa.se in speed of vehicle, the back
pressure will
(a) decrease
(b) increase
(c) remain unalfected
(d) depend on other factors
(e) none of the above.
17 The function of a distributor in an automobile is
to
(a) distribute charge, equally to all  the cylinders
(b) regulate power
(c) feed lub oil to all moving parts
(d) time the spark
(e) inject fuel at appropriate time.
173. The ratio of useful power; engine friction
exhaust gas losses; cooling water, air and oil losses
for a diesel engine is of the order of
(a) 5:25:30:50
(b) 25:35:5:35
(c) 25:5:10:60
(d) 40:30:15:15
(e) 25:5:35:35.
174. For same power and same speed, the flywheel
of a four stroke engine as compared to two-stroke
I.C. engine will be
(a) smaller
(b) bigger
(c) same size
(d) dependent on other engine parameters
(e) unpredictable.
175. Air injection in I.C. engines refers to injection of
(a) air only
(b) liquid fuel only
(c) liquid fuel and air
(d) supercharging
(e) does not exist.
176. Solid injection in I.C. engines refers to injection
of
(a) liquid fuel only
(b) liquid fuel and air
(c) solid fuel
(d) solid fuel and air
(e) does not exist.
177. The system of lubrication used for motor
cycles and scooters is by
(a) forced lubrication system
(b) splash lubrication
(c) applying grease under pressure
(d) wet sump method
(e) mixing about 5% lub oil with petrol.
178. The m.e.p. of a petrol engine first increases as
the fuel air ratio is increased and then decreases on
further increase in fuel air ratio. The m.e.p. is
maximum in the zone of
(a) lean mixture
(b) chemically correct mixture
(c) rich mixture
(d) unpredictable
(e) none of the above.
179. The specific fuel consumption for a petrol
engine first decreases with increase in fuel air ratio
and then increases with further increase in fuel air
ratio. The minimum value occurs in the range of
(a) lean mixture
(b) chemically correct mixture
(c) rich mixture
(d) unpredictable
(e) none of the above.
180. The thermal efficiency of a two cycle engine as
compared to four cycle engine is
(a) more
(b) less
(c) same
(d) more upto some load and then less
(e) it may be less or more depending on several
other factors.
181. Diesel engines as compared to petrol engines
require
(a) bigger flywheel
(b) smaller flywheel
(c) same size flywheel
(d) no flywheel
(e) flywheel whose size may be less or more
depending on several other fac-tors.
183. The tendency of a diesel engine to knock
increases, if
(a) engine speed is increased
(b) engine H.P. is increased
(c) octane number of fuel is increased
(d) conperssion ratio is increased
(e) engine has to move uphill.
184. The tendency of a petrol engine to knock
increases by
(a) supercharging
(b) scavenging
(c) increasing engine H.P,
(d) reducing the spark advance
(e) increasing cetane number of fuel.
185. Free acids in diesel oil for diesel engine lead to
(a) production of highly corrosive gases corroding
the cylinder walls and exhaust system
(b) excessive engine wear
(c) damaging of both the storage tank and the
engine
(d) deposition on engine parts
(e) excessive fuel consumption.
186. Thermal efficiency of high speed diesel engine
at design load may be of the order of
(a) 20%
(b) 35%
(c) 50%
(d) 70%
(e ) 85%.
187. The thermostat in I.C. engines permitting hot
water to go to radiator is set around
(a) 70-80°C
(b) 80-85°C
(c) 85-95°C
(d) above 100°C
(e) above 120°C.
188. The brake mean effective pressure of an I.C.
engine with increase in speed will
(a) increase
(b) decrease
(c) remain unaffected.
(d) fluctuate according to engine speed
(e) unpredictable.
189. High ash and sediment in diesel oil used in
diesel engine lead to
(a) production of highly corrosive gases corroding
the cylinder walls and ex-haust system
(b) excessive engine wear
(c) damaging of both the storage tank and the
engine
(d) deposition on engine parts
(e) blocking of exhaust pipes.
190. Mixing of fuel and air in case of dies engine
occurs in
(a) injection pump
(b) injector
(c) inlet manifold
(d) carburettor
(e) engine cylinder.
191. The advantage of reversing the flow of a in an
air cleaner is to
(a) increase velocity of air
(b) increase air flow
(c) reduce the velocity of air
(d) throw out a large percentage of foreig matter
(e) cool the air.
19 The most effective air cleaner in case diesel
engines is
(a) dry type
(b) wet type
(c) whirl type
(d) oil bath type
(e) all are equally good.
193. Fins are provided over engine cylinder
scooters for
(a) higher strength of cylinder
(b) better cooling
(c) good appearance
(d) higher efficiency
(e) easier handling and ease in manufacturing.
194. The elements of most concern in regard
pollution caused by engines are
(a) CO and C02
(b) CO and hydrocarbons
(c) C02 and hydrocarbons
(d) carbon and dust
(e) hot products of combustion
195. The preferred location of an oil cooler is
(a) before the filters
(b) after the filters
(c) between the filters
(d) before and after the filters
(e) any where.
196. The petrol from tank to the automotive ergine
is fed by
(a) gravity
(b) pump run by engine
(c) suction pressure created by, suctio stroke
(d) capillary action
(e) fuel pump.
197. In petrol engine, increase of cooling water
temperature will
(a) increase the knocking tendency
(b) decrease the knocking tendecny
(c) not affect the knocking tendency
(d) increase or decrease knocking tendency
depedning on strength and time of spark
(e) unpredictable.
207. In carburettors, the top of the fuel jet with
reference to the level in the float chamber is kept at
(a) same level
(b) slightly higher level
(c) slightly lower level
(d) may be anywhere
(e) varies from situation to situation.
208. Carburretion is done to
(a) feed petrol into cylinder
(b) govern the engine
(c) break up and mix the petrol with air
(d) heat up the charge to cylinder
(e) scavenge the cylinder.
209. Power impulses from an I.C. engine are
somoothed out by
(a) governor
(b) crank shaft
(c) gear box
(d) flywheel
(e) timing spark properly.
210. The theoretically correct mixture of air and
petrol is approximately
(a) 8 : 1
(b) 12 : 1
(c) 15 : 1
(d) 20 : 1
(e) 24: 1.
211. For low speed operation or for idling in petrol
engines, the engine requirements are for
(a) lean mixture
(b) theoretically correct mixture
(c) rich mixture
(d) any type of mixture
(e) lean/rich mixture depending upon capacity of
engine.
21 In petrol engines, advancing the spark timing will
(a) increase the knocking tendency
(b) decrease the knocking tendency
(c) not affect the knocking tendncy
(d) increase or decrease knocking tendency
depending on strenght and time of spark
(e) unpredictable.
213. The following type of carburettor is preferred
(a) concentric type
(b) eccentric type
(c) horizontal type
(d) vertical type
(e) none of the above.
214. In the passanger cars, the following type of
carburettor is preferred
(a) horizontal type
(b) downward draught type
(c) upward draught type
(c) inclined draught type
(e) any one of the above types.
215. The essential equipment for producing high
vlotage for sparking in petrol engines with battery is
(a) ignition coil
(b) ignition coil and distributor
(c) ignition coil and condenser
(d) ignition coil and contact breaker
(e) ignition coil, contact breaker and con-denser.
216. The ignition coil in diesel engines produces
voltage of the order of
(a) 6 to 12 volts
(b) 240 volts
(c) 1000 volts
(d) 20,000 volts
(e) 80,000 volts.
217. If the door of a diesel engine crankcase is
opened just after shutdown before cooling of engine,
then
(a) efficiency of engine will be poor
(b) there is a risk of explosion taking place
(c) it is the safest practice
(d) some parts may be subjected
(e) some lub oil may be wasted.
218. The thermal efficiency of a diesel engine is of
the order of
(a) 92%
(b) 68%
(c) 52%
(d) 34%
(e) 25%.
219. The thermal efficiency of a gas engine is of the
order of
(a) 92%
(b) 68%
(c) 52%
(d) 34%
(e) 25%.
220. Theoretically, the following engine should have
maximum efficiency
(a) gas engine
(b) 2-stroke S.I. engine
(c) 4-stroke S.I. engine
(d) steam engine
(e) 4-stroke C.I. engine.
221. In petrol engine using a fixed octane rating fuel
and fixed compression ratio, super charging will
(a) increase the knocking tendency
(b) decrease the knocking tendency
(c) not affect the knocking tendency
(d) increase or decrease knocking tendency
depending on strength and time of spark
(e) unpredictable.
223. High sulphur content in diesel oil used for
diesel engines leads to
(a) production of highly corrosive gases corroding
the cylinder walls and exhaust system
(b) excessive engine wear
(c) damaging of both the storage tank and the
engine
(d) deposition on engine parts
(e) reduction in thermal efficiency.
224. In open combustion chamber in diesel engines
(a) the shape and layout of the piston crown, the
inlet port, and the valve produce the turbulent effect
on fuel mixture
(b) fuel is injected into an auxiliary chamber that is
separated from the cylinder by an orifice or throat
(c) only a part of air charge is contained in an
auxiliary chamber in which the fuel starts to burn
with insufficient air which due to explosion tendency
mixes thoroughly into main cylinder charge
(d) fuel is injected at atmospheric pres¬sure
(e) there are no valves.
225. The basic requirement of a good combustion
chamber is
(a) high compression ratio
(b) low compression ratio
(c) low volumetric efficiency
(d) minimum turbulence
(e) high power output and high thermal efficiency.
226. Deposition of carbon in petrol engine cylinder
would result in increase of
(a) clearance volume
(b) swept volume
(c) compression ratio
(d) volumetric efficiency
(e) mean effective pressure.
227. Which of the following engines can work on
very lean mixture
(a) S.I. engine
(b) C.I. engine
(c) two stroke engine
(d) four stroke engine
(e) all of the above.
228. If petrol is used in a diesel engine, then
(a) higher knocking will occur
(b) efficiency will be low
(c) low power will be produced
(d) black smoke will be produced
(e) lot of fuel will remain unburnt.
229. Hot air standard diesel cycle efficiency with
increase in value of C„
(a) increases
(b) decreases
(c) remains unaffected
(d) depends on other factors
(e) unpredictable.
230. In turbulence chamber in diesel engine
(a) the shape and layout of the piston crown, the
inlet port, and the valve produce the turbulent effect
of fuel mixture
(b) fuel is injected into an auxiliary chamber that is
separated from the cylinder by an orifice or throat
(c) only a part of air charge is contained in an
auxiliary chamber in which the fuel starts to burn
with insufficient air which due to explosion tendency
mixes thoroughly into main cylinder charge
(d) there are no valves
(e) fuel is partly burnt by spark.
231. For low load operation, more suitable
(economical) engine is
(a) S.I. engine
(b) C.I. engine
(c) both are equally good
(d) multicylinder engine
(e) two stroke engine.
232. A two stroke crank compressed engine has
following ports in the cylinder
(a) suction port and exhaust port
(b) transfer port only
(c) suction port and transfer port
(d) transfer port and exhaust port
(e) suction port, exhaust port and transfer port.
233. For the same size and weight, a two stroke
engine as compared to four stroke engine will
generate power
(a) about twice
(b) about 0.5 times
(c) nearly equal
(d) about 1.7 times
(e) about 5 times.
234. A two stroke engine is usually identified by
(a) size of flywheel
(b) weight of engine
(c) type of lubrication system
(d) absence of valves
(e) location of fuel tank.
235. If diesel is fed by mistake in the oil tank of a
petrol engien, then engine will
(a) give lot of smoke
(b) detonate
(c) knock
(d) not run
(e) run for some time and then stop.
236. The thermal efficiency of a semi-diesel cycle
having fixed compression ratio and fixed quantity of
heat, with increase in pressure ratio will
(a) increase
(b) decrease
(c) remain unaffected
(d) increase/decrease depending upon engine
capacity
(e) first increase and then decrease.
245. The termal efficiency of a petrol engine at
design load is around
(a) 90%
(b) 50%
(c) 40%
(d) 30%
(e) 15%.
246. In isochronous governing, speed droop is
(a) 100%
(b) 50%
(c) 5%
(c) 30%
(e) 1%.
247. Method of governing used in petrol engine is
(a) quantity governing
(b) quality governing
(c) combined governing
(d) partial governing
(e) hit and miss governing.
248. 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
(e) For close regulation of speed, combination of
both quality and quantity governing is used.
249. Method of governing used in diesel engine is
(a) quantity governing
(b) quality governing
(c) combined governing
(d) partial governing
(e) nit and miss governing.
250. An engine has a normal speed of 960 r.p.m.
and no load speed of 1000 r.p.m. The speed droop of
governor will be about
(a) 2%
(b) 4%
(c) 8%
(d)±4%
(e) 1%.