Question

When the switch is closed, then the initial current through $1\Omega$ resistor in the given circuit is (Consider the capacitor uncharged initially)

• A. $12\text{A}$
• B. $4\text{A}$
• C. $\frac{10}{7}\text{A}$
• D. $3\text{A}$

Answer 1

The correct option is B $4\text{A}$

When an uncharged capacitor is connected with the battery at time $t=0$ its charge is zero initially, hence the potential difference across it is zero initially. At this time, the capacitor can be treated as a conducting wire.

Hence, the capacitor behaves as a short circuit. Therefore, the circuit becomes.


Now, reducing the circuit using equivalent resistance formula,


According to the loop rule,

$12-3I=0$

$\therefore I=4\text{A}$

Hence option $\left(b\right)$ is correct.