Question

A sinusoidal voltage of peak value 300 V and an angular frequency $\omega =400rad/s$ is applied to series Ca circuit, in which $R=3\Omega ,L=20mH$ and $C=625\mu F$. The peak current in the circuit is

• A. $30\sqrt{2}A$
• B. $60A$
• C. $100A$
• D. $60\sqrt{2}A$

Answer 1

Answer: (B)

$60A$

The impedance of the circuit is
$Z=\sqrt{R^2+(X_L-X_C{)}^2}$
$X_L=\omega L=400\times 20\times {10}^{-3}=8H$
$X_C=\frac{1}{\omega C}=\frac{1}{400\times 625\times {10}^{-6}}=4F$
$Z=\sqrt{(3{)}^2+(8-4{)}^2}=5$
The peak current in the circuit
$i=\frac{E}{Z}=\frac{300}{5}=60A$