Question

For the circuit shown in figure, the current supplied by battery will be

• A. $3\text{A}$
• B. $4\text{A}$
• C. $2\text{A}$
• D. $6\text{A}$

Answer 1

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

We can observe that there exists a parallel line of symmetry along the line joining points $A$ & $B$ as shown below


Therefore the perpendicular position of points with respect to the parallel line of symmetery will have the same potential. Let us give them name as ${}^{\prime }{1}^{\prime }$ & ${}^{\prime }{3}^{\prime }$ respectively.

Resistances connected between these points are of no use & can be neglected.

Redrawing the circuit:


Thus $R_{eq}=\frac{6}{2}=3\Omega$


Hence current supplied by battery,

$i=\frac{V}{R}$

$\Rightarrow i=\frac{12}{3}=4\text{A}$