Question

What is the current in the $4\Omega$ resistor when switch $S_1$ is open and switch $S_2$ is closed in the given circuit?

• A. $3.0A$
• B. $0.8A$
• C. $1.5A$
• D. $1.2A$

Answer 1

The correct option is D $1.2A$

When the switch $S_1$ is open and $S_2$ is closed, the circuit has got only the $6\Omega$ resistance and $4\Omega$ resistance connected in series to one another.

The other part of the circuit is open-circuited due to switch $S_1$ and short-circuited due to the switch $S_2$.

So, $i=\frac{V}{R_{eq}}=\frac{12}{10}$
$\Rightarrow$ $i=1.2A$