Electrical Engineering
Electrical Engineering MCQs with Answers
Electrical engineering MCQs with answers and detailed explanations for PEC, NTS, WAPDA and engineering job tests. Machines, circuits and power systems. Take a scored quiz instead →
A power electronic converter that converts DC power directly into AC power at desired voltage and frequency is called an:
AInverter
BRectifier
CCycloconverter
DChopper
A Cycloconverter is a power electronic circuit used to convert:
ADC power into high frequency AC
BAC power at one frequency directly into AC power at another frequency
CFixed DC into variable DC
DAC power into DC power
In a two-wattmeter method for 3-phase power measurement, one wattmeter reads zero when the load power factor angle is:
A60 degrees (cos phi = 0.5)
B0 degrees (cos phi = 1.0)
C90 degrees (cos phi = 0.0)
D30 degrees (cos phi = 0.866)
The Latching Current of an SCR is always:
AGreater than its Holding Current
BLess than its Holding Current
CEqual to its Holding Current
DZero
The total active power P in a balanced 3-phase system expressed in terms of line voltage V_L and line current I_L is:
A3 * V_L * I_L * cos(phi)
Bsqrt(3) * V_L * I_L * cos(phi)
Csqrt(3) * V_L * I_L * sin(phi)
DV_L * I_L * cos(phi)
When measuring power in a 3-phase 3-wire system using the two-wattmeter method, both wattmeters read equal positive values when load power factor is:
AUnity (1.0)
BZero
C0.866 leading
D0.5 lagging
The active power consumed by a pure inductor connected across an AC voltage source is:
AV * I Watts
BZero Watts
CI^2 * X_L Watts
DV^2 / X_L Watts
The RMS value of a pure sinusoidal voltage wave with peak value V_m is:
AV_m / 2
BV_m / pi
CV_m / sqrt(2)
D2 * V_m / pi
For a closed-loop control system to be stable, both Gain Margin (GM) and Phase Margin (PM) expressed in dB and degrees must be:
AEqual to infinity
BZero
CNegative
DPositive
In Norton’s equivalent circuit, the equivalent current source I_N is determined by finding the:
AShort-circuit current between output terminals
BCurrent flowing when supply voltage is zero
COpen-circuit voltage between output terminals
DMaximum load current under unity power factor