A wire of uniform cross section 'A', length '$l$' and resistance 'R' is bent into a complete circle. The equivalent resistance between any two diametrically opposite points will be:

$\frac{R}{4}$

The correct answer is Option (1) → $\frac{R}{4}$

The equivalent resistance $(R_{eq})$, between two diametrically opposite points is the parallel combination of the two resistances, each $\frac{R}{2}$.

$\frac{1}{R_{eq}}=\frac{1}{\frac{R}{2}}+\frac{1}{\frac{R}{2}}=2×\frac{2}{R}=\frac{4}{R}$

$⇒R_{eq}=\frac{R}{4}$