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This section includes 108 Mcqs, each offering curated multiple-choice questions to sharpen your Power Plant knowledge and support exam preparation. Choose a topic below to get started.
51. |
For a power plant maximum demand is 50 MW and the sum of individual maximum demands is 56 MW. Find the diversity factor. |
A. | 0.89 |
B. | 1.5 |
C. | 0.5 |
D. | 1.12 |
Answer» E. | |
52. |
Cost of power generation will be low if: |
A. | Load factor is low and diversity factor is high |
B. | Load factor is high and diversity factors is low |
C. | Load factor and diversity factor are low |
D. | Load factor and diversity factor are high |
Answer» E. | |
53. |
A 100 MW power station delivers 100 MW for 2 hours, 50 MW for 6 hours in a day and is shut down for maintenance for 45 days each year. Calculate its annual load factor? |
A. | 20% |
B. | 21% |
C. | 22.5% |
D. | 18.3% |
Answer» E. | |
54. |
Find the percentage load factor when peak demand is 436 kW, total energy use is 57200 kWh and the number of days in billing cycle is 30 days. |
A. | 20.36% |
B. | 15.60% |
C. | 18.22% |
D. | 25.75% |
Answer» D. 25.75% | |
55. |
Energy produced in a power station is 1440 MWh per day. What is the maximum demand of the station if its load factor is 0.5? |
A. | 120 MW |
B. | 280 MW |
C. | 60 MW |
D. | 140 MW |
Answer» B. 280 MW | |
56. |
In power station practice “spinning reserve” is: |
A. | Reserve generating capacity that is in operation but not in service |
B. | Reserve generating capacity that is connected to the bus and ready to take the load |
C. | Reserve generating capacity that is available for service but not in operation |
D. | The capacity of the part of the plant that remains under maintenance |
Answer» C. Reserve generating capacity that is available for service but not in operation | |
57. |
In electrical system, when there is a fixed rate per unit of energy consumed, it is called a: |
A. | flat rate tariff |
B. | two-part tariff |
C. | uniform rate tariff |
D. | block rate tariff |
Answer» D. block rate tariff | |
58. |
Plant capacity factor is the: |
A. | ratio of average load to minimum demand |
B. | ratio of minimum demand to plant capacity |
C. | ratio of maximum demand to plant capacity |
D. | ratio of average demand to plant capacity |
Answer» E. | |
59. |
A generating station has maximum demand of 25 MW, a load factor of 60% a plant capacity factor of 50% and a plant use factor of 72% Find the reserve capacity of the plant. |
A. | 8 MW |
B. | 5 MW |
C. | 20 MW |
D. | 10 MW |
Answer» C. 20 MW | |
60. |
Economic size of conductor is decided by _______. |
A. | Kirchhoff's law |
B. | Kelvin's law |
C. | Ampere's law |
D. | Faraday's law |
Answer» C. Ampere's law | |
61. |
Load shedding is done to |
A. | Improve power factor |
B. | Run the equipment efficiently |
C. | Repair the machine |
D. | Reduce peak demand |
Answer» E. | |
62. |
A consumer has annual consumption of 7,00,800 units. If his maximum demand is 200 kW. The load factor will be |
A. | 70% |
B. | 20% |
C. | 40% |
D. | 50% |
Answer» D. 50% | |
63. |
Ancillary services markets are composed of |
A. | Spinning reserves |
B. | Non-spinning reserves |
C. | Operating reserves |
D. | All of the above |
Answer» E. | |
64. |
A power plant has load factor of 0.75, capacity factor of 0.60, and use factor of 0.65. Find the reserve capacity over and above the peak load if the maximum demand is 60 MW. |
A. | 75 MW |
B. | 45 MW |
C. | 15 MW |
D. | 60 MW |
Answer» D. 60 MW | |
65. |
Capital cost of a gas turbine plant is........... than that of a steam power plant of same capacity. |
A. | Same |
B. | Less |
C. | More |
D. | Irrelevant |
Answer» C. More | |
66. |
Plant use factor is |
A. | Maximum demand/Connected load |
B. | Number of units generated/(Plant capacity × number of hours plant operated) |
C. | Average demand/plant capacity |
D. | Average load/Maximum load |
Answer» C. Average demand/plant capacity | |
67. |
Diversity factor is the ratio of _____. |
A. | sum of maximum demands of consumers/system maximum demand |
B. | maximum demand of consumers/average demand |
C. | demand of all consumers/average demand |
D. | none of these |
Answer» B. maximum demand of consumers/average demand | |
68. |
A consumer has a maximum demand of 200 kW at 40% load factor. Find the units consumed per year. |
A. | ≈ 7 × 106 kWh |
B. | ≈ 7 × 104 kWh |
C. | ≈ 7 × 103 kWh |
D. | ≈ 7 × 105 kWh |
Answer» E. | |
69. |
Determine the suitable size of a continuously rated motor for the following load curve. The load has a repeated pattern every 30 min. |
A. | 81 kW |
B. | 51 kW |
C. | 77 kW |
D. | 67 kW |
Answer» C. 77 kW | |
70. |
Load factor is 1 maximum load of generating station and the rated plant capacity are equal then: |
A. | Load factor is 1 |
B. | Capacity factor is 1 |
C. | Load factor and capacity factor are equal |
D. | Utilization factor is poor. |
Answer» D. Utilization factor is poor. | |
71. |
A generation station has the following details:Unit generated in 24 hrs = 62,500 kWh, max demand = 4000 kW and rated capacity of the plant = 6000 kW. Find the capacity factor of the plant. |
A. | 20% |
B. | 13.3% |
C. | 23.3% |
D. | 43.4% |
Answer» E. | |
72. |
Calculate annual bill of a consumer whose maximum demand is 100 kW, p.f. = 0.8 lagging and load factor = 60%. The tariff used is Rs. 50 per kVA per annum of maximum demand plus 10 paise per kWh consumed. |
A. | Rs. 58,810 |
B. | Rs. 10,550 |
C. | Rs. 65,800 |
D. | Rs. 75,250 |
Answer» B. Rs. 10,550 | |
73. |
In order to have lower cost of power generation: |
A. | The load factor and diversity factor should be low |
B. | The load factor and diversity factor should be high |
C. | The load factor should be low but diversity factor should be high |
D. | The load factor should be high but diversity factor should be low |
Answer» C. The load factor should be low but diversity factor should be high | |
74. |
For what operating time, in the case of a power plant the utilization factor and capacity factor of the plant will be the same |
A. | 4380 hours |
B. | 8760 hours |
C. | 1000 hours |
D. | 10000 hours |
Answer» C. 1000 hours | |
75. |
A demand meter is a means of indicating which of the following? |
A. | Peak power periods |
B. | A high load factor |
C. | Low kWh consumption |
D. | All options are correct |
Answer» E. | |
76. |
Diversity factor in a power system is |
A. | always less than unity |
B. | normally less than unity |
C. | always more than unity |
D. | normally more than unity |
Answer» D. normally more than unity | |
77. |
A generation station has average demand and maximum demand of 48000 kW and 96000 kW respectively. If the plant capacity factor is 0.48, the installed capacity will be: |
A. | 200000 kW |
B. | 250000 kW |
C. | 200000 kWh |
D. | 100000 kW |
Answer» E. | |
78. |
In the case where the voltage bases are same the new per unit impedance is obtained from the formula: |
A. | \(Z_{pu}^{new} = \frac{{Z_{pu}^{old}S_B^{old}}}{{S_B^{new}}}\) |
B. | \(Z_{pu}^{new} = \frac{{Z_{pu}^{old}S_B^{new}V_B^{old}}}{{S_B^{old}V_B^{new}}}\) |
C. | \(Z_{pu}^{new} = \frac{{Z_{pu}^{old}S_B^{new}}}{{S_B^{old}}}\) |
D. | \(Z_{pu}^{old} = \frac{{Z_{pu}^{new}S_B^{new}}}{{S_B^{old}}}\) |
Answer» D. \(Z_{pu}^{old} = \frac{{Z_{pu}^{new}S_B^{new}}}{{S_B^{old}}}\) | |
79. |
In India, TOD tariff is applied for which of the following consumers? |
A. | Residential consumers |
B. | Commercial shops |
C. | Industrial consumers |
D. | No consumers |
Answer» D. No consumers | |
80. |
A generating station has a connected load of 40 MW and a maximum demand of 20 MW, the units generated being 61.5 × 106 per annum. Calculate the demand factor. |
A. | 0.5% |
B. | 0.5 |
C. | 35.1% |
D. | 45% |
Answer» C. 35.1% | |
81. |
A generating station supplies the following loads to various consumers: industrial consumer, 750 MW; commercial establishment, 350 MW; domestic power, 10 MW; and domestic light, 50 MW. If the maximum demand on the station is 1000 MW, the diversity factor is: |
A. | 0.86 |
B. | 1.16 |
C. | 0.91 |
D. | 1.1 |
Answer» C. 0.91 | |
82. |
A power station’s maximum demand is 50 MW, capacity factor is 0.6 and utilization factor is 0.85. Calculate the following:a. Load factorb. Annual energy produced |
A. | Load factor = 0.5068Annual energy: 0.3 × 106 MWh |
B. | Load factor = 0.7058Annual energy: 0.3 × 107 MWh |
C. | Load factor = 0.5068Annual energy: 0.3 × 107 MWh |
D. | Load factor = 0.7058Annual energy: 0.3 × 106 MWh |
Answer» E. | |
83. |
A generating station has a connected load of 43 MW and a maximum demand of 20 MW. Calculate the demand factor. |
A. | 0.11 |
B. | 1.0 |
C. | 0.82 |
D. | 0.46 |
Answer» E. | |
84. |
Maximum demand / connected load is terned as: |
A. | Average demand |
B. | Demand factor |
C. | Load factor |
D. | Diversity factor |
Answer» C. Load factor | |
85. |
In the mercury steam cycle, the steam cycle is called? |
A. | bottoming cycle |
B. | middle cycle |
C. | topping cycle |
D. | none of the mentioned |
Answer» B. middle cycle | |
86. |
The maximum electron current per unit area provided by an emitter is given by (where J=current density, T=absolute temperature in K, ɸ=work function in keV, k=Boltzmann's constant & A=emission constant) |
A. | J= AT exp(-ɸ/kT) |
B. | J= AT (-ɸ/kT) |
C. | J= AT2 exp(-ɸ/kT) |
D. | J= exp(-Aɸ/kT2) |
Answer» D. J= exp(-Aɸ/kT2) | |
87. |
Which of these is a binary cycle? |
A. | Mercury-steam cycle |
B. | Mercury-water cycle |
C. | Mercury-Sodium cycle |
D. | None of the mentioned |
Answer» B. Mercury-water cycle | |
88. |
The engines which are operating on gas power cycle are? |
A. | cyclic |
B. | non-cyclic |
C. | either cyclic or non-cyclic |
D. | none of the mentioned |
Answer» D. none of the mentioned | |
89. |
When two vapour cycles are coupled in series and heat rejected by one is absorbed by another, the cycle is called as? |
A. | Dual vapour cycle |
B. | Binary vapour cycle |
C. | Coupled vapour cycle |
D. | None of the mentioned |
Answer» C. Coupled vapour cycle | |
90. |
In an electron beam, the average kinetic energy of an electron is given by |
A. | 2KT |
B. | 3KT |
C. | 1.5KT |
D. | 2.5KT |
Answer» B. 3KT | |
91. |
In case of mercury-steam-sulphur dioxide cycle, which is the bottoming fluid? |
A. | Mercury |
B. | Steam |
C. | Sulphur dioxide |
D. | Cannot say |
Answer» D. Cannot say | |
92. |
In centrifugal compressor, the diffuser converts |
A. | Kinetic energy into pressure energy |
B. | Pressure energy into Kinetic energy |
C. | Kinetic energy into Mechanical energy |
D. | Mechanical energy into Kinetic energy |
Answer» B. Pressure energy into Kinetic energy | |
93. |
Gas turbine is shut down by |
A. | Turning off starter |
B. | Stopping the compressor |
C. | Fuel is cut off from the combustor |
D. | Any of the mentioned |
Answer» D. Any of the mentioned | |
94. |
The specific heat of the ideal working fluid used in vapour power cycle |
A. | should be constant |
B. | should be large |
C. | should be small |
D. | none of the mentioned |
Answer» D. none of the mentioned | |
95. |
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» C. when steam is extracted only from the last stage of steam turbine | |
96. |
What is the maximum content of moisture allowed at the turbine exhaust in the steam power plant? |
A. | 0.5 |
B. | 0.6 |
C. | 0.3 |
D. | 0.15 |
Answer» E. | |
97. |
How can we differentiate Rankine cycle from Carnot cycle? |
A. | Heat addition process of Rankine cycle is reversible isothermal whereas heat addition process of Carnot cycle is reversible isobaric |
B. | Heat addition process of Rankine cycle is reversible isobaric whereas heat addition process of Carnot cycle is reversible isothermal |
C. | Heat addition process of Rankine cycle is reversible isentropic whereas heat addition process of Carnot cycle is reversible isothermal |
D. | Both cycles are identical except the working fluid used |
Answer» C. Heat addition process of Rankine cycle is reversible isentropic whereas heat addition process of Carnot cycle is reversible isothermal | |
98. |
Which of the following is (are) used as starter for a gas turbine |
A. | An Internal combustion engine |
B. | A steam turbine |
C. | An auxiliary electric motor |
D. | All of the mentioned |
Answer» E. | |
99. |
The total loss in a tertiary cycle is? |
A. | sum of losses in the individual cycles |
B. | product of losses in the individual cycles |
C. | sum of products of individual losses |
D. | none of the mentioned |
Answer» C. sum of products of individual losses | |
100. |
In a regenerative feed heating cycle, the optimum value of the fraction of steam extracted for feed heating |
A. | decreases with increase 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 mentioned |
Answer» C. is unaffected by increase in Rankine cycle efficiency | |