Question

Seven $1\Omega$ resistances are connected as shown in the figure. Resistance of the conducting wires is negligible. Effective resistance between $A$ and $B$ is:

Answer 1

Now equivalent circuit becomes :

$R_{eq}=\frac{2R\times \frac{R}{2}}{2R+\frac{R}{2}}=\frac{2R}{5}$