বর্তনীর তুল্য রোধ কত?

Here,

$\begin{aligned} \frac{1}{R_{P}} & =\frac{1}{R_{2}}+\frac{1}{R_{3}}+\frac{1}{R_{4}} \\ & =\frac{1}{R}+\frac{1}{R}+\frac{1}{R} \\ & =\frac{3}{R}\end{aligned}$

$\begin{array}{l}\therefore R_{p}=\frac{R}{3} \\ \therefore R_{s}=R_{1}+R_{p}=\frac{R}{3}+R=\frac{4 R}{3}\end{array}$