Question

A wire of resistance 5 ohm is bend in the form of closed circle. What is the resistance between 2 points at the ends of any diameter of the circle?

Answer 1

The diametrically opposite points divides the resistance into half of the total resistance.

Resistance of each semi circle $R_1=R_2=\frac{5}{2}=2.5\Omega$

These resistance are connected in parallel.

So, equivalent resistance $R_{eq}=\frac{R_1{R}_2}{R_1+R_2}=\frac{2.5\times 2.5}{2.5+2.5}=1.25\Omega$