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
$i_{1}=\frac{12 \times 18}{18}=12 \,A$
$ i_{2}=\frac{6 \times 18}{18}=6 \,A$

Now $12 \,A$ current is entering in parallel combination of $3 \Omega$ and $6 \Omega$ again from current distribution law
$i_{1}=\frac{6 \times 12}{9}=8\, A$
$i_{2}=\frac{3 \times 12}{-1}=4 A$
$\therefore $ Potential difference across $3\, \Omega$ resistance
$=8 \times 3=24\, V$