Question

Figure shows a circuit that contains three identical resistors with resistance $R=9.0\Omega$ each, two identical inductors with inductance $L=2.0mH$ each, and an ideal battery with $emf\epsilon =18V$. The current '$i$' through the battery just after the switch closed is, ....

• A. $0$ ampere
• B. $4mA$
• C. $0.4A$
• D. $4A$

Answer 1

Answer: (D)

$4A$

At $t=0$, (switched on) capacitor behaves as short circuit
Induct behaves as open circuit

Here $R_{eq}=\frac{R}{2}$
so, $i=\frac{\in }{R_{eq}}=\frac{18\times 2}{9}=4A$