Alternating Current

In an a.c. circuit the instantaneous current and emf are represented as \(\mathrm{I}=\mathrm{I}_0, \sin [\omega \mathrm{t}-\pi / 6]\) and \(\mathrm{E}=\mathrm{E}_0 \sin [\omega \mathrm{t}+\pi / 3]\) respectively. The voltage leads the current by