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Electrical Engineering Objective Questions { Transformers }

106. No-load current of a transformer has
A. as high magnitude and low power h factor
B. as high magnitude and high power h factor
C. small magnitude and high power factor
D. small magnitude and low power factor

107. Create the secondary leakage flux
A. less e.m.f will be the secondary induced.
B. less e.m.f will be the primary induced
C. less volt age will be the primary terminal
D. none of the above

108. The pur pose of providing a step-up iron core in transformer is
A. to pr ovide coupling between primary and secondary
B. to inc rease the magnitude of mutual flux
C. to d ecrease the magnitude of magnetizing current

109.  The power transformer is a constant
A. voltage device
B. current device
C. power device
D. main flux device

110. Two transformers operating in parallel will share the load depending upon their
A. leakage reactance
B. per unit impedance
C. efficiencies
D. ratings

111.  If R2 is the resistance of secondary winding of the transformer and K is the transformation ratio then the equivalent secondary resistance referred to primary will be
A. R2 x K2
B. R2/K2
C. R221K2
D. R221K

112. What will happen if the transformers working in parallel are not connected with regard to polarity?
A. The power factor of the two transformers will be different from the power factor of common load
B. Incorrect polarity will result in dead short circuit
C. The transformers will not share load in proportion to their kVA ratings
D. none of the above

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