Question

In the electrical network shown in the figure, the potential difference across $3\Omega$ resistance will be

• A. 12 V
• B. 2.4 V
• C. 24 V
• D. 36 V

Answer 1

Answer: (C)

As $3\Omega$ and $6\Omega$ resistances are in parallel their equivalent resistance will be $2\Omega$. Here $2\Omega$ and $4\Omega$ are in series, their equivalent resistance will be $6\Omega$.

From current distribution law
$i_1=\frac{12\times 18}{18}=12A$
$i_2=\frac{6\times 18}{18}=6A$

Now $12A$ current is entering in parallel combination of $3\Omega$ and $6\Omega$ again from current distribution law
$i_1=\frac{6\times 12}{9}=8A$
$i_2=\frac{3\times 12}{-1}=4A$
$\therefore$ Potential difference across $3\Omega$ resistance
$=8\times 3=24V$