POWER PLANT(POWER GENERATION) IMPORTANT MCQ ( Mock Test ) Part-2

 51. In case of impulse steam turbine

(a) there is enthalpy drop in fixed and moving blades
(b) there is enthalpy drop only in moving blades
(c) there is enthalpy drop in nozzles
(d) none of the above
Ans: c

52. The pressure on the two sides of the impulse wheel of a steam turbine
(a) is same
(b) is different
(c) increases from one side to the other side
(d) decreases from one side to the other side
Ans: a

53. In De Laval steam turbine
(a) the pressure in the turbine rotor is approximately same as in con¬denser
(b) the pressure in the turbine rotor is higher than pressure in the condenser
(c) the pressure in the turbine rotor gradually decreases from inlet to exit
from condenser
(d) none from the above
Ans: a

54. Parson’s turbine is
(a) pressure compounded steam turbine
(b) simple single wheel, impulse steam turbine
(c) simple single wheel reaction steam turbine
(d) multi wheel reaction steam turbine
Ans: d

55. For Parson’s reaction steam turbine, degree of reaction is
(a) 75%
(b) 100%
(c) 50%
(d) 60%
Ans: c

56. Reheat factor in steam turbines depends on
(a) exit pressure only
(b) stage efficiency only
(c) initial pressures and temperature only
(d) all of the above
Ans: c

57. The value of reheat factor normally varies from
(a) 0.5 to 0.6
(b) 0.9 to 0.95
(c) 1.02 to 1.06
(d) 1.2 to 1.6
Ans: c

58. Incase of reaction steam turbine
(a) there is enthalpy drop both in fixed and moving blades
(b) there is enthalpy drop only in fixed blades
(c) there is enthalpy drop only in moving blades
(d) none of the above
Ans: a

59. Curtis turbine is
(a) reaction steam turbine
(b) pressure velocity compounded steam turbine
(c) pressure compounded impulse steam turbine
(d) velocity compounded impulse steam turbine
Ans: b

60. Rateau steam turbine is
(a) reaction steam turbine
(b) velocity compounded impulse steam turbine
(c) pressure compounded impulse steam turbine
(d) pressure velocity compounded steam turbine
Ans: c


61. Steam turbines are governed by the following methods
(a) Throttle governing
(b) Nozzle control governing
(c) By-pass governing
(d) all of the above
Ans: d

62. In steam turbines the reheat factor
(a) increases with the increase in number of stages
(b) decreases with the increase in number of stages
(c) remains same irrespective of number of stages
(d) none of the above
Ans: a

63. The thermal efficiency of the engine with condenser as compared to
without condenser, for a given pressure and temperature of steam, is
(a) higher
(b) lower
(c) same as long as initial pressure and temperature is unchanged
(d) none of the above
Ans: a

64. In jet type condensers
(a) cooling water passes through tubes and steam surrounds them
(b) steam passes through tubes and cooling water surrounds them
(c) steam and cooling water mix
(d) steam and cooling water do not mix
Ans: c

65. In a shell and tube surface condenser
(a) steam and cooling water mix to give the condensate
(b) cooling water passes through the tubes and steam surrounds them
(c) steam passes through the cooling tubes and cooling water surrounds them
(d) all of the above varying with situation
Ans: b

66. In a surface condenser if air is removed, there is
(a) fall in absolute pressure maintained in condenser
(b) rise in absolute pressure maintained in condenser
(c) no change in absolute pressure in the condenser
(d) rise in temperature of condensed steam
Ans: a

67. The cooling section in the surface condenser
(a) increases the quantity of vapour extracted along with air
(b) reduces the quantity of vapour extracted along with air
(c) does not affect vapour quantity extracted but reduces pump capacity of air
extraction pump
(d) none of the above
Ans: b

68. Edward’s air pump
(a) removes air and also vapour from condenser
(b) removes only air from condenser
(c) removes only un-condensed vapour from condenser
(d) removes air alongwith vapour and also the condensed water from condenser
Ans: d

69. In a steam power plant, the function of a condenser is
(a) to maintain pressure below atmospheric to increase work output from the
primemover
(b) to receive large volumes of steam exhausted from steam prime mover
(c) to condense large volumes of steam to water which may be used again in
boiler
(d) all of the above
Ans: d

70. In a regenerative surface condenser
(a) there is one pump to remove air and condensate
(b) there are two pumps to remove air and condensate
(c) there are three pumps to remove air, vapour and condensate
(d) there is no pump, the condensate gets removed by gravity
Ans: b

71. Evaporative type of condenser has
(a) steam in pipes surrounded by water
(b) water in pipes surrounded by steam
(c) either (a) or (b)
(d) none of the above
Ans: a

72. Pipes carrying steam are generally made up of
(a) steel
(b) cast iron
(c) copper
(d) aluminium
Ans: a

73. For the safety of a steam boiler the number of safety valves fitted
are
(a) four
(b) three
(c) two
(d) one
Ans: c

74. Steam turbines commonly used in steam power station are
(a) condensing type
(b) non-condensing type
(c) none of the above
Ans: a

75. Belt conveyer can be used to transport coal at inclinations upto
(a) 30°
(b) 60°
(c) 80°
(d) 90°
Ans: a

76. The maximum length of a screw conveyer is about
(a) 30 metres
(b) 40 metres
(c) 60 metres
(d) 100 metres
Ans: a

77. The efficiency of a modern boiler using coal and heat recovery
equipment is about
(a) 25 to 30%
(b) 40 to 50%
(c) 65 to 70%
(d) 85 to 90%
Ans: d

78. The average ash content in Indian co als is about
(a) 5%
(b) 10%
(c) 15%
(d) 20%
Ans: d

79. Load center in a power station is
(a) center of coal fields
(b) center of maximum load of equipments
(c) center of gravity of electrical system
Ans: c

80. Steam pressure in a steam power station, which is usually kept
now-a-days is of the order of
(a) 20 kgf/cm2
(b) 50 kgf/cm2
(c) 100 kgf/cm2
(d) 150 kgf/cm2
Ans: d

81. Economisers improve boiler efficiency by
(a) 1 to 5%
(b) 4 to 10%
(c) 10 to 12%
Ans: b

82. The capacity of large turbo-generators varies from
(a) 20 to 100 MW
(b) 50 to 300 MW
(c) 70 to 400 MW
(d) 100 to 650 MW
Ans: b

83. Caking coals are those which
(a) burn completely
(b) burn freely
(c) do not form ash
(d) form lumps or masses of coke
Ans: d

84. Primary air is that air which is used to
(a) reduce the flame length
(b) increase the flame length
(c) transport and dry the coal
(d) provide air around burners for get¬ting optimum combustion
Ans: c

85. Secondary air is the air used to
(a) reduce the flame length
(b) increase the flame length
(c) transport and dry the coal
(d) provide air round the burners for getting optimum combustion
Ans: d

86. In coal preparation plant, magnetic separators are used to remove
(a) dust
(b) clinkers
(c) iron particles
(d) sand
Ans: c

87. Load carrying capacity of belt conveyor is about
(a) 20 to 40 tonnes/hr
(b) 50 to 100 tonnes/hr
(c) 100 to 150 tonnes/hr
(d) 150 to 200 tonnes/hr
Ans: b

88. Method which is commonly applied for unloading the coal for small
power plant is
(a) lift trucks
(b) coal accelerators
(c) tower cranes
(d) belt conveyor
Ans: b

89. Bucket elevators are used for
(a) carrying coal in horizontal direction
(b) carrying coal in vertical direction
(c) carrying coal in any direction
Ans: b

90. The amount of air which is supplied for complete combustion is called
(a) primary air
(b) secondary air
(c) tertiary air
Ans: b

91. In ______ system fuel from a central pulverizing unit is delivered to
a bunker and then to the various burners
(a) unit
(b) central
(c) none of the above
Ans: b

92. Under-feed stokers work best for _______ coals high in volatile
matter and with caking tendency
(a) anthracite
(b) lignite
(c) semibituminous and bituminous
Ans: c

93. Example of overfeed type stoker is
(a) chain grate
(b) spreader
(c) travelling grate
(d) all of the above
Ans: d

94. Where unpulverised coal has to be used and boiler capacity is large,
the stoker which is used is
(a) underfeed stoker
(b) overfeed stoker
(c) any
Ans: b

95. TravelUng grate stoker can burn coals at the rates of
(a) 50—75 kg/m per hour
(b) 75—100 kg/m per hour
(c) 100—150 kg/m per hour
(d) 150—200 kg/m2 per hour
Ans: d

96. Blowing down of boiler water is the process
(a) to reduce the boiler pressure
(b) to increase the steam temperature
(c) to control the solid concentration in the boiler water by removing some of
the concentrated saline water
(d) none of the above
Ans: c

97. The value of the reheat factor is of the order of
(a) 0.8 to 1.0
(b) 1.0 to 1.05
(c) 1.1 to 1.5
(d) above 1.5
Ans: c

98. Compounding of steam turbine is done for
(a) reducing the work done
(b) increasing the rotor speed
(c) reducing the rotor speed
(d) balancing the turbine
Ans: c

99. Deaerative heating is done to
(a) heat the water
(b) heat the air in the water
(c) remove dissolved gases in the water
Ans: c

100. Reheat factor is the ratio of
(a) isentropic heat drop to useful heat drop
(b) adiabatic heat drop to isentropic heat drop
(c) cumulative actual enthalpy drop for the stages to total is isentropic
enthalpy heat drop
Ans: c

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