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WorksheetsFundamentals of AC Circuits
Total questions: 15
Worksheet time: 8mins
All over the world, sinusoidal voltages and currents are selected for generation of electrical power because:
produce low iron and copper losses
offer less interference to nearby communication lines
produce less disturbance in the network
All the above
RMS value for an AC quantity can be applied to
Symmetrical waveforms
Unsymmetrical waveforms
Both symmetrical & unsymmetrical waveforms
None of the above
The steady or DC current which when flowing through a circuit for a given time period produces the same heat as produced by the AC current flowing through the same circuit for the same time period is called as _________ of an AC quantity.
RMS value
Maximum value
Instantaneous value
Average value
Definitions of power factor of a series R-L-C circuit are correct except
Ratio of net reactance and impedance
Ratio of kW and kVA
Ratio of R and Z
Ratio of W and VA
If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is
A sinusoid of double the frequency
A sinusoid of the same frequency
A sinusoid of half the original frequency
None of the above
All the rules and laws of D.C. circuit also apply to A.C. circuit containing
Capacitance only
Inductance only
Resistance only
All above
In an A.C. circuit power is dissipated in
Resistance only
Inductance only
Capacitance only
In all the three passive elements
In a pure inductive circuit if the supply frequency is reduced to 1/2, the current will
Be reduced by half
Be doubled
Be four times as high
Be reduced to one fourth
The time constant of a series R-C circuit is given by
R/C
RC2
R2C
RC
A heater is rated as 230 V, 10 kW, 50 Hz AC. The value 230 V refers to
Average voltage
r.m.s. voltage
Peak voltage
None of the above
In an AC. circuit, a low value of kVAR compared with kW indicates
Low efficiency
High power factor
Unity power factor
Maximum load current
Which of the following statements pertains to resistors only?
Can dissipate considerable amount of power
Oppose sudden changes in voltage
Connecting them in parallel increases the total value
Both (a) and (b)
Pure inductive circuit takes power from the A.C. line when
Applied voltage decreases but current increases
Applied voltage increases but current decreases
Both applied voltage and current increase
Both applied voltage and current decrease
The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is
4 kVAR
6 kVAR
8 kVAR
2 kVAR
Capacitive susceptance is a measure of
Reactive power in a circuit
The extent of neutralization of reactive power in a circuit
A purely capacitive circuit's ability to pass current
A purely capacitive circuit's ability to resist the flow of current
