Top 100+ Power Plant Engineering Objective Questions & Answers
Top 100+ Power Plant Engineering Objective Questions & Answers
1. The effect of considering friction in steam nozzles for the same pressure ratio leads to ______
a) increase in dryness fraction of exit steam
b) decrease in dryness fraction of exit steam
c) no change in the quality of exit steam
d) decrease or increase of dryness fraction of exit steam depending upon inlet quality
Answer: increase in dryness fraction of exit steam
2. The isentropic expansion of steam through nozzle for the steam initially dry saturated at inlet is approximated by equation.
a) pv = C
b) pv1A = C
c) pv1i = C
d) pv
Answer: pv
3. The effect of considering friction losses in steam nozzle for the same pressure ratio leads to ______
a) increase in exit velocity from the nozzle
b) decrease in exit velocity from the nozzle
c) no change in exit velocity from the nozzle
d) increase or decrease depending upon the exit quality of steam
Answer: decrease in exit velocity from the nozzle
4. 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
Answer: increases with the increase in number of stages
An Introduction to Thermal Power Plant Engineering and Operation: For Power Plant Professionals5. Steam turbines are governed by the following methods ______
a) Throttle governing
b) Nozzle control governing
c) By-pass governing
d) all of the above
Answer: all of the above
6. 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
Answer: higher
7. 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
Answer: steam and cooling water mix
8. 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
Answer: fall in absolute pressure maintained in condenser
9. 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
Answer: cooling water passes through the tubes and steam surrounds them
10. 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
Answer: reduces the quantity of vapour extracted along with air
11. 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
Answer: removes air alongwith vapour and also the condensed water from condenser
12. 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
Answer: all of the above
13. 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
Answer: there are two pumps to remove air and condensate
14. 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
Answer: there is enthalpy drop in nozzles
Thermal Power Plants: Modeling, Control, and Efficiency Improvement15. 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
Answer: is same
16. 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
Answer: the pressure in the turbine rotor is approximately same as in condenser
17. 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
Answer: there is enthalpy drop both in fixed and moving blades
18. 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
Answer: pressure velocity compounded steam turbine
19. 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
Answer: pressure compounded impulse steam turbine
20. 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
Answer: multi wheel reaction steam turbine
21. For Parson’s reaction steam turbine, degree of reaction is ______
a) 75%
b) 100%
c) 50%
d) 60%
Answer: 50%
22. 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
Answer: initial pressures and temperature only
23. 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
Answer: 1.02 to 1.06
24. The draught produced by steel chimney as compared to that produced by brick chimney for the same height is ______
a) less
b) more
c) same
d) may be more or less
Answer: more
25. In a boiler installation the natural draught is produced ______
a) due to the fact that furnace gases being light go through the chimney giving place to cold air from outside to rush in
b) due to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column
c) due to the fact that at the chimney top the pressure is more than its environmental pressure
d) all of the above
Answer: due to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column
26. The draught produced, for a given height of the chimney and given mean temperature of chimney gases ______
a) decreases with increase in outside air temperature
b) increases with increase in outside air temperature
c) remains the same irrespective of outside air temperature
d) may increase or decrease with increase in outside air temperature
Answer: decreases with increase in outside air temperature
27. The draught produced by chimney of given height at given outside temperature ______
a) decreases if the chimney gas temperature increases
b) increases if the chimney gas temperature increases
c) remains same irrespective of chimney gas temperature
d) may increase or decrease
Answer: increases if the chimney gas temperature increases
28. For forced draught system, the function of chimney is mainly ______
a) to produce draught to accelerate the combustion of fuel
b) to discharge gases high up in the atmosphere to avoid hazard
c) to reduce the temperature of the hot gases discharged
d) none of the above
Answer: to discharge gases high up in the atmosphere to avoid hazard
29. Artificial draught is produced by ______
a) induced fan
b) forced fan
c) induced and forced fan
d) all of the above
Answer: all of the above
30. The draught in locomotive boilers is produced by ______
a) forced fan
b) chimney
c) steam jet
d) only motion of locomotive
Answer: steam jet
31. For the same draught produced the power of induced draught fan as compared to forced draught fan is ______
a) less
b) more
c) same
d) not predictable
Answer: more
32. Artificial draught is produced by ______
a) air fans
b) steam jet
c) fan or steam jet
d) all of the above
Answer: all of the above
33. The artificial draught normally is designed to produce ______
a) less smoke
b) more draught
c) less chimney gas temperature
d) all of the above
Answer: all of the above
34. 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
Answer: steam in pipes surrounded by water
35. Pipes carrying steam are generally made up of ______
a) steel
b) cast iron
c) copper
d) aluminium
Answer: steel
36. For the safety of a steam boiler the number of safety valves fitted are ______
a) four
b) three
c) two
d) one
Answer: two
37. Steam turbines commonly used in steam power station are ______
a) condensing type
b) non-condensing type
c) Both a&b
d) none of the above
Answer: condensing type
38. Belt conveyer can be used to transport coal at inclinations upto ______
a) 30°
b) 60°
c) 80°
d) 90°
Answer: 30°
39. The maximum length of a screw conveyer is about ______
a) 30 metres
b) 40 metres
c) 60 metres
d) 100 metres
Answer: 30 metres
40. 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%
Answer: 85 to 90%
41. The average ash content in Indian co als is about ______
a) 5%
b) 10%
c) 15%
d) 20%
Answer: 20%
42. Load centre in a power station is ______
a) centre of coal fields
b) centre of maximum load of equip-ments
c) centre of gravity of electrical system
d) none of the above
Answer: centre of gravity of electrical system
43. 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
Answer: 150 kgf/cm2
44. In ______ system fuel from a central pulverizing unit is delivered to a bunker and then to the various burners
a) unit
b) central
c) both a&b
d) none of the above
Answer: central
45. Under-feed stokers work best for _______ coals high in volatile matter and with caking tendency
a) anthracite
b) lignite
c) semibituminous and bituminous
d) none of the above
Answer: semibituminous and bituminous
46. Example of overfeed type stoker is ______
a) chain grate
b) spreader
c) travelling grate
d) all of the above
Answer: all of the above
47. 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
d) all of the above
Answer: overfeed stoker
48. 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
Answer: 150—200 kg/m2 per hour
49. 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
Answer: to control the solid concentration in the boiler water by removing some of the concentrated saline water
50. Deaerative heating is done to ______
a) heat the water
b) heat the air in the water
c) remove dissolved gases in the water
d) none of the above
Answer: remove dissolved gases in the water
51. 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
d) none of the above
Answer: cumulative actual enthalpy drop for the stages to total is isentropic enthalpy heat drop
52. 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
Answer: 1.1 to 1.5
53. 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
Answer: reducing the rotor speed
54. The commercial sources of energy are ______
a) solar, wind and biomass
b) fossil fuels, hydropower and nuclear energy
c) wood, animal wastes and agriculture wastes
d) none of the above
Answer: fossil fuels, hydropower and nuclear energy
55. 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
Answer: reducing the rotor speed
56. In India largest thermal power station is located at ______
a) Kota
b) Sarni
c) Chandrapur
d) Neyveli
Answer: Chandrapur
57. The percentage O2 by Veight in atmospheric air is ______
a) 18%
b) 23%
c) 77%
d) 79%
Answer: 23%
58. The percentage 02 by volume in atmosphere air is ______
a) 21%
b) 23%
c) 77%
d) 79%
Answer: 21%
59. The proper indication of incomplete combustion is ______
a) high CO content in flue gases at exit
b) high CO2 content in flue gases at exit
c) high temperature of flue gases
d) the smoking exhaust from chimney
Answer: high CO content in flue gases at exit
60. The main source of production of biogas is ______
a) human waste
b) wet cow dung
c) wet livestock waste
d) all of the above
Answer: all of the above
61. India’s first nuclear power plant was installed at ______
a) Tarapore
b) Kota
c) Kalpakkam
d) none of the above
Answer: Tarapore
62. In fuel cell, the ______ energy is converted into electrical energy.
a) mechanical
b) chemical
c) heat
d) sound
Answer: chemical
63. The energy radiated by sun on a bright sunny day is approximately ______
a) 700 W/m2
b) 800 W/m2
c) 1 kW/m2
d) 2 kW/m2
Answer: 1 kW/m2
64. Thorium Breeder Reactors are most suitable for India because ______
a) these develop more power
b) its technology is simple
c) abundance of thorium deposits are available in India
d) these can be easily designed
Answer: abundance of thorium deposits are available in India
65. The overall efficiency of thermal power plant is equal to ______
a) Rankine cycle efficiency
b) Carnot cycle efficiency
c) Regenerative cycle efficiency
d) Boiler efficiency x turbine efficiency x generator efficiency
Answer: Regenerative cycle efficiency
66. Rankine cycle efficiency of a good steam power plant may be in the range of ______
a) 15 to 20 percent
b) 35 to 45 percent
c) 70 to 80 percent
d) 90 to 95 percent
Answer: 35 to 45 percent
67. Rankine cycle operating on low pressure limit of pi an 1 high pressure limit of p2 ______
a) has higher the rnal efficiency than the carnot cycie operating between same pressure limits
b) has lower the”nal efficiency than carnot cycle operating between same pressure limit?
c) has same thermal efficiency as carnot cycle operating between same pressure limits
d) may be more or less depending upon the magnitude ofpi and/>2
Answer: has higher the rnal efficiency than the carnot cycie operating between same pressure limits
68. Rankine efficiency of a steam power plant ______
a) improves in summer as compared to that in winter
b) improves in winter as compared to that in summer
c) is unaffected by climatic conditions
d) none of the above
Answer: improves in winter as compared to that in summer
69. Carnot cycle comprises of ______
a) two isentropic processes and two constant volume processes
b) two isentropic processes and two constant pressure processes
c) two isothermal processes and three constant pressure processes
d) none of the above
Answer: two isentropic processes and two constant pressure processes
70. In Rankine cycle the work output from the turbine is given by ______
a) change of internal energy between inlet and outlet
b) change of enthaply between inlet and outlet
c) change of entropy between inlet and outlet
d) change of temperature between inlet and outlet
Answer: change of enthaply between inlet and outlet
71. Regenerative cycle thermal efficiency ______
a) is always greater than simple Rankine thermal efficiency
b) is greater than simple Rankine cycle thermal efficiency only when steam is bled at particular pressure
c) is same as simple Rankine cycle thermal efficiency
d) is always less than simple Rankine cycle thermal efficiency
Answer: is always greater than simple Rankine thermal efficiency
72. In a regenerative feed heating cycle, the optimum value of the fraction of steam extracted for feed heating ______
a) decreases with in crease in Rankine cycle efficiency
b) increases with increase in Rankine cycle efficiency
c) is unaffected by increase in Rankine cycle efficiency
d) none of the above
Answer: increases with increase in Rankine cycle efficiency
73. Economisers improve boiler efficiency by ______
a) 1 to 5%
b) 4 to 10%
c) 10 to 12%
d) none of the above
Answer: 4 to 10%
74. 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
Answer: 50 to 300 MW
75. Caking coals are those which ______
a) burn completely
b) burn freely
c) do not form ash
d) form lumps or masses of coke
Answer: form lumps or masses of coke
76. 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 getting optimum combustion
Answer: transport and dry the coal
78. 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
Answer: provide air round the burners for getting optimum combustion
79. In coal preparation plant, magnetic separators are used to remove ______
a) dust
b) clinkers
c) iron particles
d) sand
Answer: iron particles
80. 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
Answer: 50 to 100 tonnes/hr
81. 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
Answer: coal accelerators
82. Bucket elevators are used for ______
a) carrying coal in horizontal direction
b) carrying coal in vertical direction
c) carrying coal in any direction
d) none of the above
Answer: carrying coal in vertical direction
83. The amount of air which is supplied for complete combustion is called ______
a) primary air
b) secondary air
c) tertiary air
d) none of the above
Answer: secondary air
84. In a regenerative feed heating cycle, the greatest economy is affected ______
a) when steam is extracted from only one suitable point of steam turbine
b) when steam is extracted from several places in different stages of steam turbine
c) when steam is extracted only from the last stage of steam turbine
d) when steam is extracted only from the first stage of steam turbine
Answer: when steam is extracted from several places in different stages of steam turbine
85. The maximum percentage gain in Regenerative feed heating cycle thermal efficiency ______
a) increases with number of feed heaters increasing
b) decreases with number of feed heaters increasing
c) remains same unaffected by number of feed heaters
d) none of the above
Answer: increases with number of feed heaters increasing
86. In regenerative cycle feed water is heated by ______
a) exhaust gases
b) heaters
c) draining steam from the turbine
d) all of the above
Answer: draining steam from the turbine
87. Reheat cycle in steam power plant is used to ______
a) utilise heat of flue gases
b) increase thermal efficiency
c) improve condenser performance
d) reduce loss of heat
Answer: increase thermal efficiency
88. Mercury is a choice with steam in binary vapour cycle because it has ______
a) higher critical temperature and pressure
b) higher saturation temperature than other fluids
c) relatively low vapourisation pressure
d) all of the above
Answer: all of the above
89. Binary’vapour cycles are used to ______
a) increase the performance of the condenser
b) increase the efficiency of the plant
c) increase efficiency of the turbine
d) all of the above
Answer: increase the efficiency of the plant
90. A steam power station requires space ______
a) equal to diesel power station
b) more than diesel power station
c) less than diesel power station
d) all of the above
Answer: more than diesel power station
91. Economiser is used to heat ______
a) air
b) feed water
c) flue gases
d) all above
Answer: feed water
92. The modern steam turbines are ______
a) impulse turbines
b) reaction turbines
c) impulse-reaction turbines
d) none of the above
Answer: impulse-reaction turbines
93. The draught which a chimney produces is called ______
a) induced draught
b) natural draught
c) forced draught
d) balanced draught
Answer: natural draught
94. For the induced draught the fan is located ______
a) near bottom of chimney
b) near bottom of furnace
c) at the top of the chimney
d) anywhere permissible
Answer: near bottom of chimney
95. The pressure at the furnace is minimum in case of ______
a) forced draught system
b) induced draught system
c) balanced draught system
d) natural draught system
Answer: balanced draught system
96. The efficiency of chimney is approximately ______
a) 80%
b) 40%
c) 20%
d) 0.25%
Answer: 0.25%
97. The isentropic expansion of steam through nozzle for the steam initially superheated at inlet is approximated by equation
a) pvls=C
b) pv1126 = C
c) pv1A = C
d) pv = C
Answer: pvls=C
98. The ratio of exit pressure to inlet pressure for maximum mass flow rate per unit area of steam through a nozzle when steam is initially dry saturated is ______
a) 0.6
b) 0.578
c) 0.555
d) 0.5457
Answer: 0.578
99. The ratio of exit pressure to inlet pressure of maximum mass flow rate per area of steam through a nozzle when steam is initially superheated is ______
a) 0.555
b) 0.578
c) 0.5457
d) 0.6
Answer: 0.5457
100. The critical pressure ratio of a convergent nozzle is defined as ______
a) the ratio of outlet pressure to inlet pressure of nozzle
b) the ratio of inlet pressure to outlet pressure of nozzle
c) the ratio of outlet pressure to inlet pressure only when mass flow rate per unit area is minimum
d) the ratio of outlet pressure to inlet pressure only when mass flow rate = c
Answer: the ratio of outlet pressure to inlet pressure only when mass flow rate = c
Solar thermal power plant (MCQ) Objective Questions and answers
1. Which of the following processes take place in solar distillation
a) evaporation
b) condensation
c) both (a) and (b)
d) solidification
Answer: both (a) and (b)
2. Un-glazed solar collectors are designed primarily for
a) space heating
b) crop drying
c) pre-heat make up ventilation air
d) all of the above
Answer: pre-heat make up ventilation air
3. The function of a solar collector is to convert ______
a) Solar Energy into Electricity
b) Solar Energy radiation
c) Solar Energy thermal energy
d) Solar Energy mechanical energy
Answer: Solar Energy thermal energy
4. Most of the solar radiation received on earth surface lies within the range of ______
a) 0.2 to 0.4 microns
b) 0.38 to 0.78 microns
c) 0 to 0.38 microns
d) 0.5 to 0.8 microns
Answer: 0.2 to 0.4 microns. Read More >>
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