ELECTRICAL ENGINEERING MCQ_07

Q.116 If the percentage reactance of the system upto the point of fault is 20% and the base KVA is 10000 the short circuit KVA is
A. 10 MVA
B. 20MVA
C. 50 MVA
D. 60 MVA
Ans.: C

Q.117 All the peripheral devices connected to a computer require power to work. Which of the following voltage is required for the motherboard to work?
A. AC
B. positive cycle of sine wave
C. D.C
D. negative cycle of sine wave
Ans.: C

Q.118 The purpose of embedding the damper winding in the pole face of a synchronous motor is to
A. eliminating hunting and provide adequate starting torque
B. eliminates losses on account of air friction
C. reduce winding losses
D. reduce bearing friction
Ans.: A

Q.119 Hysteresis in an instrument means
A. the repeatability of the instruments
B. the reliability of the instrument
C. the change in the same reading when the input is first increased and then decreased
D. the inaccuracy due to change in temperature
Ans.: C

Q.120 The mutual inductance between two unity coupled coils of 9H and 4 H is
A. 36 H
B. 13 H
C. 2.2 H
D. 6 H
Ans.: D

Q.121 If the fault current is 2000A, the relay plug setting is 50% and the CT ratio is 400/5, the plug setting multiplier will be
A. 25
B. 10
C. 15
D. 50
Ans.: B

Q.122 If the excitation of a synchronous motor generator us fails, it acts as a
A. Synchronous motor
B. synchronous generator
C. induction motor
D. induction generator
Ans.: D

Q.123 The motor used in ceiling fans is
A. split phase motor
B. capacitor start capacitor run motor
C. capacitor start motor
D. universal motor
Ans.: B

Q.124 The purpose of inter-poles in d.c machines is to nullify
A. the demagnetizing effect of armature mmf
B. the cross magnetizing effect of armature mmf
C. the reactance voltage
D. both the cross magnetizing mmf and the reactance voltage
Ans.: D

Q.125 The effect of electric shock on the human body is depends on
A. voltage
B. duration
C. current
D. all of the above
Ans.: D

Q.126 A fixed step by step procedure for finding the solution of a problem on computer us called
A. Hardware
B. Logic
C. Algorithm
D. Software
Ans.: C

Q.127 What type of insulators is used if the direction of the transmission line is to be changed?
A. pin type
B. suspension type
C. strain type
D. Shackle type
Ans.: C

Q.128 An IDMT relay provides
A. an inverse time current characteristic
B. a definite time characteristic for low values of the fault current and an inverse characteristic for high values of the fault current
C. a definite time current characteristic
D. an inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current
Ans.: D

Q.129 An a.c series circuit has R= 6Ω , XL = 20Ω and Xc= 12Ω. The circuit power factor will be
A. 0.8 lagging
B. 0.5 leading
C. 0.6 lagging
D. 0.6 leading
Ans.: D
Q.130 The purpose if skewing of rotor slots in an induction motors
A. to reduce the magnetic hum of the motor
B. to increase the distribution factor
C. to reduce the locking tendency of the rotor
D. to increase the breath factor
Ans.: C

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