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MCQ of Transformer page-1MCQ of Transformer page-2MCQ of Transformer page-3MCQ of Transformer page-4MCQ of Transformer page-5MCQ of Transformer page-6MCQ of Transformer page-7MCQ of Transformer page-8MCQ of Transformer page-9MCQ of Transformer page-10MCQ of Transformer page-11MCQ of Transformer page-12MCQ of Transformer page-13MCQ of Transformer page-14MCQ of Transformer page-15MCQ of Transformer page-16MCQ of Transformer page-17MCQ of Transformer page-18MCQ of Transformer page-19MCQ of Transformer page-20MCQ of Transformer page-21MCQ of Transformer page-22MCQ of Transformer page-23MCQ of Transformer page-24MCQ of Transformer page-25MCQ of Transformer page-26MCQ of Transformer page-27

Index

SymbolsTransformerRelayPower-SystemBasic-electricalACSR-ConductorCircuit-BreakerInterview-questions-of-Basic-ElectricityInterview-questions-of-transformerInsulatorCurrent-TransformerMCQMCQ-powersystemThermal-power-stationInterview-questions-of-Power-SystemPower-ElectronicsInterview-questions-of-Underground-CableInterview-questions-of-IlluminationIlluminationMCQ-of-ElectronicsMCQ-of-Basic-ElectricalMCQ-of-Transformers MCQ-of-D.C-motor MCQ-of-D.C-generatorsMCQ-Control-SystemMCQ-Measurementsmcq-of-Generation-power-systemMCQ-of-Induction-MotorMCQ-of-Transmission-DistributionMCQ-of-Electrical-MachinesMCQ-of-Alternator-and-Synchronous-MotorsMCQ-Electric-Power

MCQ of Transformer page-22


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111. Two transformers are connected in parallel and share loads in the ratio of their kVA ratings when their ohmic impedance

A) In direct ratio of their ratings
B) In inverse ratio of their rating
C) Equal
D) Purely reactive.

Ans : (B)

112. The voltage regulation of a transformer at full load 0.85 pF lagging is 5%. Its voltage regulation at full load 0.85 pF leading will be

A) negative
B) same
C) positive
D) reduce and may even became negative.

Ans : (D)

113. A transformer has maximum efficiency when (Pi = core loss, Pc = copper loss) ratio of Pi/Pc is

A) 1
B) 2
C) 1.5
D) 0.5.

Ans : (A)

114. In a transformer, the core loss is found to be 46 W at 50 Hz and is 80 W at 70 Hz, both losses being measured at the same peak flux density. The hysteresis loss and eddy current loss 60 Hz is

A) 11 W, 20 W
B) 16 W, 30 W
C) 30 W, 45 W
D) 22 W, 40 W.

Ans : (D)

115. If the secondary of a 1 : 10 step-up transformer is connected to the primary of a 1 : 5 step-up transformer, the total transformation ratio will be

A) 15
B) 30
C) 50
D) 2500.

Ans : (C)

116. A single-phase transformer has resistance and reactance of 0.2 pu and 0.6 pu respectively. Its pu voltage regulation at 0.8 pf lagging would be

A) 0.36
B) 0.42
C) 0.52
D) 0.62.

Ans : (C)

117. A transformer having 100 turns of primary side is applied with 200 V ac. In order to get 400 V ac secondary side the number of turns on the secondary side must be

A) 100
B) 50
C) 800
D) 200.

Ans : (D)

118. Power transformers are usually designed to have maximum efficiency

A) near full load
B) at 75 % of full load
C) at 50 % of full load
D) between 50 % and 75 % of full load.

Ans : (A)

119. Distribution transformers are usually designed to have maximum efficiency

A) near full load
B) near 75% of full load
C) near 50 % of full load
D) near no load.

Ans : (C)

120. In a transformer, it is difficult to measure the efficiency by output-input measurement methods because

A) The output is sinusoidal and hence cannot be measured
B) Losses are abnormally high
C) Efficiency of transformer is usually high and hence extremely accurate measurements will be necessary
D) Output is out of phase with respect to input.

Ans : (C)


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