Question

In the circuit shown, no charge is initially given to the capacitor. At $t=0$, the switch S is closed. The maximum charge on the capacitor at any instant is :

• A. $5.625\mu C$
• B. $5.625\times {10}^{-4}C$
• C. $5.625\times {10}^{-5}C$
• D. $5.625mC$

Answer 1

The correct option is D $5.625mC$

When, the charge on the capacitor is maximum, there will be no current in the arm of capacitor.

$i=\frac{dq}{dt}$ where $q$=charge on capacitor

when $q=max⟹i=\frac{dq}{dt}=0$

Hence, there will be no current in the circuit when the charge on capacitor is maximum.

Hence, no e.m.f across either resistor or inductor.

Hence, potential across capacitor, $V=75V$

Hence , charge on capacitor, $q_o=CV=75\times 75\mu C$

$q_o=5.625mC$

Answer-(D)