Question

A wire of 8 ohm resistance is doubled on it calculate the new resistance of wire

Answer 1

Answer:

Lets say the wire is a cylinder.

Volume before and after stretching is constant assuming no deformation.

1> r1^2*l1 = r2^2*l2 = V

Ratio of Resistance before and after stretching :

R1/R2 = (l1/r1^2) / ( l2/r2^2) = (l1^2/V ) / ( l2^2/V ) = ( l1/l2) ^2 = (1/2)^2 = 1/4

Therefore , R2 = R1 * 4 = 32 Ohm