Question

Voltage and current in an AC circuit are given by $ V=5\sin \left( 100\pi t-\frac{\pi }{6} \right) $ and $ I=4\sin \left( 100\pi t+\frac{\pi }{6} \right) $

• A. voltage leads the current by $ 30{}^\circ $
• B. current leads the voltage by $ 30{}^\circ $
• C. current leads the voltage by $ 60{}^\circ $
• D. voltage leads the current by $ 60{}^\circ $
• E. current and voltage are in phase

Answer 1

Answer: (C)

Net phase difference between current and voltage
$ =\frac{\pi }{6}-\left( -\frac{\pi }{6} \right)=\frac{\pi }{3}=60{}^\circ $
Hence, current leads the voltage by
$ 60{}^\circ $ .