Power Plant Engineering Objective Questions
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 con¬denser
(c) the pressure in the turbine rotor gradually decreases from inlet to exit from condenser
(d) none from the above
Ans: a
54. 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
55. 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
56. 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
57. 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
58. For Parson’s reaction steam turbine, degree of reaction is
(a) 75%
(b) 100%
(c) 50%
(d) 60%
Ans: c
59. 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
60. 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
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