141. If two sinusoids of the same fraquency but of different amplitudes and phase difference are added, the resultant is a sinusoid of

A. the same frequency

B. double the original frequency.

C. half the original frequency

D. none of these

142. All the rules and laws which apply to de networks also apply to ac networks consisting of

A. resistance

B. inductance

C. capacitance

D. all of these

143. In ac circuits the power curve is a sine wave having

A. same frequency as that of voltage

B. double the frequency of the voltage

C.

D.(c) half the frequency of the voltage

144. If an alternating triangular voltage is applied to a resistor, the shape of the curreq,t waveform will be

A. triangular waveform

B. sawtooth waveform

C. sinusoidal waveform

D. square waveform

145. The magnetic field energy in an inductor changes from maximum value to minimum value in 5m sec when connected to an ac source. The frequency of the source is

A. 20 Hz

B. 50 Hz

C. 200 Hz

D. 500 Hz

146. With the increase in supply frequency, the inductive reactance of a circuit

A. increases

B. decreases

C. remains unchanged

D. unpredictable

147. Pure inductive circuit has zero

A. pf

B. power consumed

C. heat produced

D. current drawn

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