A wire of resistance `4 Omega` is stretched to four times of its original length resistance of wire now becomes

Options

A. `4Omega`
B. `8Omega`
C. `64Omega`
D. `16Omega`

Answer

C

Explanation

`R_(1)=4 Omega, l_(2)=4 l_(1), R_(2)=?`
`(R_(2))/(R_(1))=((l_(2))/(l_(1)))^(2)`
`:.R_(2)=((4l_(1))/(l_(1)))^(2)xxR_(1)=16xx4=64Omega`.