Circuit Theory Quiz | Circuit Theory Short Questions and Answers

Questions
41 Power factor of electric bulb is
A zero
B lagging
C leading
D unity

Answer: unity
42 In a purely inductive circuit
A actual power is zero
B reactive power is zero
C apparent power is zero
D none of above is zero

Answer: actual power is zero
43 In any A.C. circuit always
A apparent power is more than actual power
B reactive power is more than apparent power
C actual power is more than reactive power
D reactive power is more than actual power

Answer: apparent power is more than actual power
44 Inductance of coil
A is unaffected by the supply frequency
B decreases with the increase in supply frequency
C increases with the increase in supply frequency
D becomes zero with the increase in supply frequency

Answer: increases with the increase in supply frequency
45 In a circuit containing R, L and C, power loss can take place in
A C only
B L only
C R only
D all above

Answer: R only
46 In a pure inductive circuit
A the current is in phase with the voltage
B the current lags behind the voltage by 90°
C the current leads the voltage by 90°
D the current can lead or lag by 90°

Answer: the current lags behind the voltage by 90°
47 In a pure resistive circuit
A current lags behind the voltage by 90°
B current leads the voltage by 90°
C current can lead or lag the voltage by 90°
D current is in phase with the voltage

Answer: current is in phase with the voltage
48 In the case of an unsymmetrical alternating current the average value must always be taken over
A unsymmetrical part of the wave form
B the quarter cycle
C the half cycle
D the whole cycle

Answer: the whole cycle
49 The power factor at resonance in R-L- C parallel circuit is
A zero
B 0.08 lagging
C 0.8 leading
D unity

Answer: unity
50 The transient currents are associated with the
A changes in the stored energy in the inductors and capacitors
B impedance of the circuit
C applied voltage to the circuit
D resistance of the circuit

Answer: changes in the stored energy in the inductors and capacitors
51 The double energy transient occur in the
A purely inductive circuit
B R-L circuit
C R-C circuit
D R-L-C circuit

Answer: R-L-C circuit
52 The square waveform of current has following relation between r.m.s. value and average value.
A r.m.s. value is equal to average value
B r.m.s. value of current is greater than average value
C r.m.s. value of current is less than average value
D none of the above

Answer: r.m.s. value is equal to average value
53 The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing through a given circuit for a given time produces
A the more heat than produced by A.C. when flowing through the same circuit
B the same heat as produced by A.C. when flowing through the same circuit
C the less heat than produced by A.C. flowing through the same circuit
D none of the above

Answer: the same heat as produced by A.C. when flowing through the same circuit
54 In a loss-free R-L-C circuit the transient current is
A oscillating
B square wave
C sinusoidal
D non-oscillating

Answer: sinusoidal
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