Question

A wire is drawn such that its radius changes from r to 2r.The new resistance is
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Answer 1

Answer:

New resistance is 4 times the old one.

Explanation:

Volume of wire remains same because the material of the wire hasn't changed.

V = V’

So, the new area of cross section is half the previous one.

So, from these equations,

R = 4r

So, the resistance is four times the old one.