Electrical Engineering

A.C Fundamentals, Circuits And Circuit Theory MCQs

Practice A.C Fundamentals, Circuits And Circuit Theory MCQs for competitive exams.

A.C Fundamentals, Circuits And Circuit Theory MCQs

Practice questions from this topic.

The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is

  1. A. 12 kW
  2. B. 22 kW
  3. C. 32 kW
  4. D. 64 kW
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In an A.C. circuit power is dissipated in

  1. A. Resistance only
  2. B. Inductance only
  3. C. Capacitance only
  4. D. None of the above
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At very low frequencies a series R-C circuit behaves as almost purely

  1. A. Resistive
  2. B. Inductive
  3. C. Capacitive
  4. D. None of the above
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The series and parallel resonance on L-C circuit' differs in that

  1. A. Series resistance needs a low-resistance source for sharp rise in current
  2. B. Series resonance needs a high-resistance source for sharp increase in current
  3. C. Parallel resonance needs a low-resistance source for a sharp increase in impedance
  4. D. Parallel resonance needs a low-resistance source for a sharp rise in line current
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Wire-wound resistors are unsuitable for use at high frequencies because they

  1. A. Create more electrical noise
  2. B. Are likely to melt under excessive eddy current heat
  3. C. Consume more power
  4. D. Exhibit unwanted inductive and capacitive effects
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In a loss-free R-L-C circuit the transient current is

  1. A. Oscillating
  2. B. Square wave
  3. C. Sinusoidal
  4. D. Non-oscillating
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If resistance is 20 ohms. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be

  1. A. 0.001 s
  2. B. 0.1 s
  3. C. 10 s
  4. D. 100 s
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Ohm is unit of all of the following except

  1. A. Inductive reactance
  2. B. Capacitive reactance
  3. C. Resistance
  4. D. Capacitance
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For a sine wave with peak value Emax ___________ 8.30. the average value is

  1. A. 0.636 Emax
  2. B. 0.707 Emax
  3. C. 0.434 EWc
  4. D. lAUEmax
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The frequency of an alternating current is

  1. A. The speed with which the alternator runs
  2. B. The number of cycles generated in one minute
  3. C. The number of waves passing through a point in one second
  4. D. The number of electrons passing through a point in one second
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All definitions of power factor of a series R-L-C circuit are correct except

  1. A. Ratio of net reactance and impedance
  2. B. Ratio of kW and kVA
  3. C. Ratio of J and Z
  4. D. Ratio of W and VA
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The best place to install a capacitor is

  1. A. Very near to inductive load
  2. B. Across the terminals of the inductive load
  3. C. Far away from the inductive load
  4. D. Any where
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