Question

Consider a series L-R circuit in which $L=\frac{1}{\pi }H$ and resistance $R=100\Omega$. When the circuit is connected to A.C. source 220 V, 50 Hz. Find the current drawn from the source.

Answer 1

Impedance $z=\sqrt{R^2+(\omega L{)}^2}=\sqrt{R^2+4{\pi }^2{f}^2{L}^2}=\sqrt{(100{)}^2+(100{)}^2}=100\sqrt{2}\Omega$

$X_L=2\pi fL=100\Omega$

Hence $l_{mm}=\frac{V_{mm}}{Z}=\frac{200}{100\sqrt{2}}=11\sqrt{2}A$