Question

Three equal resistances each of value $R$ are joined as shown in the figure. The equivalent resistance between $M$ and $N$ is

• A. R
• B. 2R
• C. R/2
• D. R/3

Answer 1

Answer: (D)

All $3$ resistances are in parallel.
$\therefore$ By $\frac{1}{R}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$
or $\frac{1}{R_{eq}}=\frac{1}{R}+\frac{1}{R}+\frac{1}{R}$
$\Rightarrow R_{eq}=\frac{R}{3}$