71. 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

72. The double energy treansient occur in the

A. purely inductive circuit

B. R-L circuit

C. R-C circuit

D. R-L-C circuit

73. The transient currents are associated with the

A. changes in the stored energy in the inductors and capacitors

B. impedance of teh circuit

C. applied voltage to the circuit

D. resistance of th circuit

74. The power factor at resonance in R-L-C parallel circuit is

A. zero

B. 0.08 lagging

C. 0.8 leading

D. unity

75. In the case of an unsymmetrical alternating current the average value must always be taken over

A. unsymmetrical part of the wave from

B. the quarter cycle

C. the half cycle

D. the whole cycle

76. In a pure resistive circuit

A. current lags behind the voltage by 900

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

77. In a pure inductive circuit

A. the current is in phase which the voltage

B. the current lags behind the voltage by 90?

C. the current leads the voltage by 90?

D. the current canlead or lag by 90?

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