134. The voltagein a circuit follows the law v = 100 sin cot If the frequency is 25 Hz, how long will it take for the voltageto rise to 50 volts?

A. line current

B. two voltages can be used

C. phase sequence can be easily changed

D. it is a simple arrangement

135. The negative maximum of a cosine wave occurs at

A. 30?

B. 45?

C. 90?

D. 180?

136. Ina series R-L circuit the instantaneous voltage is given by (wL)2 ',sin (cot + tan-1 (1) The above equation indicates that

A. the current lags the voltage by ancoL angle tan R

B. the current leads the voltage by an_1 angle tan ?R

C. the current lags the voltage by 60?

D. the current leads the voltage by 60?

137. The r.m.s. value of pure cosine function is

A. 0.5 of peak value

B. 0.707 of peak value

C. same as peak value

D. zero

138. Ohm is unit of all of the following except

A. inductive reactance capacitive reactance

B. resistance

C. capacitance

D.

139. If A = 8L30? and B = 2L15? the value of A/B will be

A. 4Z15?

B. 6L30?

C.8Z15?

D. none of the above

140. The series and parallel resonance on L-C circuit differs in that

A. series resistance needs a low resistance source for sharp rise in current series

B. needs a lowresistance source for a sharp increase in impedance

C.resonance needs a high-resistance source for sharp increase in current parallel resonance

D. parallel resonance needs a lowresistance source for a sharp rise in line current

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