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The length and readius of a wire is l a...

The length and readius of a wire is l and r respectively. Its resistance is R. After hammering the radius of the wire is made (r/2) then the new resistance will be

A

4R

B

8R

C

12R

D

16R

Text Solution

Verified by Experts

The correct Answer is:
D
For same mass of wire, `R prop (1)/(r^(4))`
`:.(R')/(R)=(r/r)^(4)=(((r//r))/(2))^(4)=16`
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