Question

if radius of a metallic wire becomes n times its resistance becomes-
(a).n^{2} times \\
(b).\frac{1}{n^{2} } times \\
(c).n^{4} times\\
(d).\frac{1}{n^{4} } \\
pls give me with correct explantion....!!!!!!!!.....?

Answer 1

Explanation:

$r = rho \times \frac{l}{a}$

where a is area of cross section

when radius becomes n times

the resistance becomes

$\frac{1}{ {n}^{2} } times$