127. An alternating current of frequency 50 Hz and maximum value 200 A given as
A. i =200 sin 628 t.
B. i = 200 sin 314 t.
C.i= 100 sin 314 t
D. i = 100 tri sin 157t
128. A sine wave has a frequency of 50 Hz. Its angular frequency will be
A. 50 radians/sec
B. 50 n radians/sec
C. 100 radians/sec
D. 100 n radians/sec
129. The time period of an alternating quantity is 0.02 second. Its frequency will be
A.25 Hz
B.50 Hz
C. 100 Hz
D. 0.02 Hz
130. In a multipolar (P-pole) machine runing at a speed of N rpm, the frequency of generated emf is equal to
A. ?60PN
B. 120PN
C.
D.PN
131. Average value of an unsymmetrical alterating quantity is calculated over the
A. whole cycle
B. half cycle
C. unsymmetrical part of the waveform
D. none of these
132. A 50 Hz ac voltage is measured with a moving iron voltmeter and a rectifier type ac voltmeter connected in parallel. If the meter reading are VI and V2 respectively and the meters are free from calibration erros, then the form factor of the ac voltage may be estimated as
A. zero
B. B w2U2
C. ?Bw2L/2
D. 2Bw2L
133. Form factor is the ratio of
A. average value to rms value
B. rms value to average value
C. peak value to average value
D. peak value to rms value
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