Question

viil) The wire of length and resistance ris stretched so that its radius of cross section is
halved. What is its new resistance.
a)5R
byer
04R
d) 16R​

Answer 1

Answer:

4R

Explanation:

We know that,

R=¶L/A. (Just consider ¶ as rho )

Now,

A'= πr'²

A'=π(r/2)²

A'=π(r²/4)

A'=A/4

Again,

R'=¶L/A'

R'=¶L/A/4

R'=4¶L/A

Therefore,

R'=4R