Question

A wire of resistance 10 ohm is bent in form of closed square what is the effective resistance between the two points at the ends of any diagonal of the square

Answer 1

The resistance of each side of square will be 2.5

then the set will be like two sides in each of the two branches

each branch have net resistance of 5 [ two 2.5 resistors in series ]

by formula for equivalent resistance of two resistors in parallel the answer is 2.5

Answer 2

Explanation:

resistance of each side of square =10/4 = 2.5 ohm

resistance R1 = 2.5 + 2.5 = 5 ohm

resistance R2 = 2.5 + 2.5 = 5 ohm

R1 & R2 are resistances of two opposite parts of the diagonal of square.

hence resistance at two ends of diagonal will be

(1/R) = (1/R1) + (1/R2)

= (1/5)+(1/5)= (2/5)

R = 5/2 = 2.5 ohm