Question

A RC series circuit of R$=15\Omega$ and $C=10\mu F$ is connected to $20$ volt DC supply for very long time. Then capacitor is disconnected from circuit and connected to inductor of $10$mH. Find amplitude of current.

• A. $0.2\sqrt{10}$A
• B. $2\sqrt{10}$A
• C. $0.2$A
• D. $\sqrt{10}$A

Answer 1

The correct option is A $0.2\sqrt{10}$A

Given : $C=10\mu F$ $V_o=20$ volts $L=10mH$
Amplitude of the current $I_o=Q_{o}w=\left(C{V}_o\right)\frac{1}{\sqrt{LC}}=\sqrt{\frac{C}{L}}{V}_o$
$⟹$ $I_o=\sqrt{\frac{10\times {10}^{-60}}{10\times {10}^{-3}}}\times 20=0.2\sqrt{10}A$