Question:
Five equal resistances are connected in a network as shown in figure. The net resistance between the points $A$ and $B$ is :
Correct Option: , 3
Solution:
$(3)$
It is balanced wheat stone bridge
So, we know that
$\mathrm{R}_{1} \mathrm{R}_{\mathrm{A}}=\mathrm{R}_{2} \mathrm{R}_{3}$
$\frac{\mathrm{R}_{1}}{\mathrm{R}_{2}}=\frac{\mathrm{R}_{3}}{\mathrm{R}_{4}}$
$\operatorname{Req}=\frac{2 R \times 2 R}{2 R+2 R}$
$\frac{4 R^{2}}{4 R} \Rightarrow R$