356050 The peak value of an alternating e.m.f. E is given by E=E0cosωt is 10volts and its frequency is 50Hz. At time t=1600s, the instantaneous emf is
E=EocosωtEo=10 Vf=50HZ⇒ω=2π×50=100πt=1600sThe instantaneous value of emf=10cos(100π×1600)=10cos(π6)=53 V
356051 An ac voltage is represented by E=2202cos(50π)t How many times will the current becomes zero in 1s?
E=Eocosωt∴ω=50π2πf=50π⇒f=25HzIn one cycle ac current becomes zero twice therefore, 50 times the current becomes zero in 1s.
356052 An ac generator produced an output voltage E=170sin(377t) volts, where t is in seconds. The frequency of ac voltage is
2πv=377⇒v=60.03Hz
356053 The peak voltage of 440Volt AC mains is equal to (in Volt)
V0=2⋅Vr.m.s =2×440=622 VoltSo correct option is (3).