Question

A wire of resistance 10ohm is bent to form a complete circle. find it's resistance between diametrically opposite point​

Answer 1

When a resistance is bent in a circle, the resistors are are connected in parallel.

Each of the resistors (the 2 parallel resistors of the circle) have a resistance of 10 ohms.

So we get the following-

Req = R1 x R2 / R1R2 (where Req is equivalent resistance in parallel connections)

OR

1/Rp =1/R1 + 1/R2 ( where Rp is resistance in parallel )

1/Rp = 1/10 + 1/10

1/Rp = 2/10

Rp = 10/2

Rp = 5 ohms