Question

If the switches $S_1,S_2$ and $S_3$ in the figure are arranged such that current through the battery is minimum, find the voltage across points $A$ and $B$.(rounded off to nearest integer)

Answer 1

Current through battery will be minimum when all switches are open.

So for equivalent circuit as drawn in figure:

Net resistance $\left(netR\right)=12\Omega$ , Voltage $=24V$

Current through circuit $=\frac{V}{netR}=\frac{24}{12}=2A$

Voltage across $AB=l\times \frac{1}{2}=2\times \frac{1}{2}=1V$