Mechanical Engineering-Steam Boilers, Engines, Nozzles and Turbines Important MCQ PDF

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: a2.       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.    Pulverised
fuel is used for
(a)      better
burning
(b)      more
calorific value
(c)      less
radiation loss
(d)      medium
sized units
(e)      stoker
fired boilers.
Ans: a

177.    Calorific
value of coal is of the order of
(a)      200-400
kcal/kg
(b)      800-1200
kcal/kg
(c)      2000-4000
kcal/kg
(d)      5000-8000
kcal/kg
(e)      8000-10,000
kcal/kg.
Ans: c

178.    Evaporative
capacity of boiler is expressed as
(a)      kg
of steam produced
(b)      steam
pressure produced
(c)      kg
of fuel fired
(d)      kg
of steam produced per kg of fuel fifed
(e)      kg
of water evaporated.
Ans: d

179.    Boiler
parameters are expressed by
(a)      tonnes/hr.
of steam
(b)      pressure
of steam in kg/cm2
(c)      temperature
of steam in °C
(d)      all
of the above
(e)      none
of the above.
Ans: d

180. The
condition of steam in boiler drum is always
(a) dry
(b) wet
(c) saturated
(d) supersaturated
(e) superheated.
Ans: b

181.    The
balanced draft furnace is one using
(a)      induced
draft fan and chimney
(b)      induced
draft fan and forced draft fan
(c)      forced
draft fan and chimney
(d)      any
one of the above
(e)      none
of the above.
Ans: b

182.    In
ordetjo obtain superheated steam, a superheater is added in an existing boiler.
As as result, furnace vacuum will
(a)      remain
unaffected
(b)      improve
(c)
worsen
(d)      may
improve/worsen depending on size
(e)      unpredictable.
Ans: c

183.    Maximum
energy loss in a boiler occurs due to
(a)      unburnt
carbon in ash
(b)      incomplete
combustion
(c)      ash
content
(d)     flue gases
(e)     radiation losses.
Ans: d

184.    Overfire
burning is the phenomenon of
(a)      supply
of excess, air
(b)      supply
of excess coal
(c)      burning
CO and unburnts in upper zone of furnace by supplying more air
(d)      fuel
bed firing
(e)      none
of the above.
Ans: c

185.    Which
is not the correct statement about moisture in coal
(a)      inherent
moisture and surface mois¬ture are different things
(b)      in
some coals moisture may be present upto 40%
(c)      some
moisture in coal helps in better burning which is not possible with completely
dry coal
(d)      it
increases thermal efficiency
(e)      moisture
in coal is removed before firing by heating it with hot air.
Ans: d

186.    Deaeration
of feed water is carried out because it reduces
(a)      cavitation
of .boiler feed pumps
(b)      corrosion
caused by oxygen
(c)      heat
transfer coefficient
(d)      pH
value of water
(e)      weight
of water to be handled.
Ans: b

187.    A
supercritical boiler is one that operates above the pressure and temperature of
following values
(a)      100
kg/cm2 and 540°C
(b)      1
kg/cm2 and 100°C
(c)      218
kg/cm2 abs and 373°C
(d)      218 kg/cm2 abs and 540°C
(e)      100 kg/cm2 abs and 373°C
Ans: c

188.    Natural
water circulation, by convection in water tube boilers, with increase in
pressure of boiler
(a)     increases
(b)     decreases
(c)     remains
unaffected
(d)     first
increases and then decreases
(e)     first
decreases and then increases.
Ans: b

189.    The
steam temperature with increase in load in case of a boiler fitted with
radiation superheater
(a)     increases
(b)     decreases
(c)     remains
unaffected
(d)     first
increases and then decreases
(e)     unpredictable.
Ans: b

190.   During
storage, the heating value of coal
(a)     increases
(b)     decreases
(c)     remains
constant
(d)     may
increase or decrease depending upon the method of storage
(e)     none
of the above.
Ans: b

191.    The
relative heat absorption for successively added equal areas of boiler
convection heating surfaces
(a)     increases
(b)     decreases
(c)     remains
unaffected
(d)     first
increases and then decreases
(e)     first
decreases and then increases.
Ans: b

192.    Film
boling occurs at
(a)      very
low pressure
(b)      atmospheric
pressures
(c)      medium
pressures
(d)      very
high pressures
(e)      none
of the above.
Ans: d

193.Fire
tube boilers are limited to a maximum design working pressure of
(a) 1 kg/cm
(b) 6 kg/cm
(c) 17 kg/cm2
(d) 100 kg/cm2
(e) 250 kg/cm2.
Ans: c

194.For
the same diameter and thickness of tube, a water tube boiler compared to a fire
tube boiler has
(a)      more
heating surface
(b)      less
heating surface
(c)      equal
heating surface
(d)      heating
surface depends on other parameters
(e)      none
of the above.
Ans: a

195.In
water wall furnace, the heat is transferred to the water-walls by
(a)      convection
(b)      radiation
(c)      conduction
(d)      radiation
and conducton
(e)      radiation
and convection.
Ans: b

196.   Relative
percentage of heat absorbed through the heat transfer of
(i)     furnace water wall,
(ii)     boiler bank,
(Hi)   superheater,
(iv)   economiser,
(v)    airheater of a typical boiler of 200 MW capacity would be of the order of
(a)    48:20:15:7:10
(b)   10:7:15:20:48
(c)   20:48:7:15:10
(d)   7:15:20:10:48
(e)   48:15:10:7:20.
Ans: a

197.    The
feed check valve is used in order to
(a)      regulate
flow of boiler water
(b)      check
level of water in boiler drum
(c)      recirculate
unwanted feed water
(d)      allow
high pressure feed water to flow to drum and not allow reverse flow to take
place
(e)      none
of the above.
Ans: d

198.The
size of a boiler drum in pulverised fuel fired boiler,as its size and capacity,
(steam pressure and flow ratings) increase
(a)      increases
(b)      decreases
(c)      remains
unchanged
(d)      increases/decreases
depending on steam temperature requirements
(e)      unpredictable.
Ans: b

199.    Feed
water conditioning in thermal power plants in done to
(a)      reduce
hardness and for removal of solids
(b)      increase
efficiency-of thermal power plant
(c)      increase
*heat transfer rate
(d)      increase
steam parameters
(e)      all
of the above.
Ans: a

200. The
basic job of feed water treatment in boilers is to overcome the problem of
(a)    corrosion
(b)    scale
(c)    carryover
(d)    embitterment
(e)    all of the above.
Ans: e

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Mechanical Engineering Compressors,Gas Turbines And Jet Engines Important MCQ PDF
Mechanical Engineering-Compressors, Gas Turbines and Jet Engines Important MCQ PDF

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