Question

The switch in the circuit is closed at $t=0$. Find the current through the cell immediately after the switch is closed.

• A. $1\text{A}$
• B. $2\text{A}$
• C. $3\text{A}$
• D. $4\text{A}$

Answer 1

The correct option is B $2\text{A}$

At $t=0$ current in the circuit starts to grow and it has not reached steady state.
$\therefore$Immediately after the switch is closed, inductor will act as $\infty$ resistance $\&$ current will not enter the branch containing inductor.


circuit is effectively as shown, hence $2\Omega$ adjacent to inductor will be of no use.
$i=\frac{V}{R_{eq}}$
$\therefore i=\frac{6}{(1+2)}=2\text{A}$