# Multiple Choice Question (MCQ) of Power Systems page-5

61. As the transmission voltage increases the volume of the conductor

a) Increases
b) Decreases
c) Will not change
d) Will increase proportionately

Ans: (b)

62. The power transmission capacity of the transmission line is

a) Proportional to the square of the operating voltage
b) Inversely proportional to the voltage
c) Proportional to the voltage
d) Inversely proportional to the square of the voltage

Ans: (a)

63. The overall capital cost of the transmission decreases the voltage of transmission increases.

a) true
b) false

Ans: (a)

64. Which of the following power plant has the maximum efficiency?

a) Thermal power plant
b) Hydro-electric power plant
c) Atomic Reactor
d) MHD

Ans: (c)

65. The corona loss in the transmission line can be reduced by increasing spacing between the conductors or the diameter of the conductors.

a) true
b) false

Ans: (a)

66. The bundle conductors are preferred for EHV transmission line because

a) It is easy to fabricate thin conductors and combine them to make a bundle
b) Overall inductance of the line is reduced and corona loss and radio influences are minimum
c) Height of the tower is reduced and hence cheap transmission
d) Fabrication of the conductor is cheap
e) Of erection difficulties

Ans: (b)

67. EHV d.c. transmission over large distance is cheaper than EHV a.c. transmission

a) true
b) false

Ans: (a)

68. The percentage reactance is defined as

a) The percentage of the ratio of change in reactance in transient condition to the total reactance of the machine
b) The percentage of the ratio of change in reactance in transient condition of the total resistance of the machine
c) The percentage of the ratio of voltage drop due to reactance synchronous machine to the rated voltage when full load rating current is flowing
d) Either (a) and (c)

Ans: (c)

69. If the secondary of the transformer having the reactance of 4% is short circuited with normal voltage applied to the primary the symmetrical short circuit current will be

a) 4 times of the full load current
b) 25 times of the full load current
c) 2 times of the full load current
d) 8 times of the full load current
e) 40 times of the full load current

Ans: (b)

70. If the base kVA is 25,000 then a 5000 kVA alternator with 8% reactance will have

a) A 4% reactance
b) A 40% reactance
c) A 16% reactance
d) A 20% reactance

Ans: (b)

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