Question

Five equal resistances are connected in a network as shown in figure. The net resistance between the points $A$ and $B$ is

• A. $\frac{3R}{2}$
• B. $\frac{R}{2}$
• C. $R$
• D. $2R$

Answer 1

The correct option is C $R$

Redrawing the circuit we observe that it is a balanced wheatstone bridge .

So, we know that ,

$R_1{R}_4=R_2{R}_3$

$\frac{R_1}{R_2}=\frac{R_3}{R_4}$

If this condition satisfies then $R_{DE}$ become redundant and here it satisfies the equations. Thus, $R_{DE}$ is redundant.

$R_{eq}=\frac{2R\times 2R}{2R+2R}=\frac{4R^2}{4R}$ $=$ $R$