The resistance of a 10 m long wire is 10 `Omega`. Its length is increased by 25% by stretching the wire uniformly. The the resistance of the wire will be

Options

A. 12.5 `Omega`
B. 14.5 `Omega`
C. 15.6 `Omega`
D. 16.6 `Omega`

Answer

C

Explanation

`R = (rho lambda)/(A)`
For given problem `R prop lambda^(2)`
Hence `(R_(1))/(R_(2)) = (lambda_(1)^(2))/(lambda_(2)^(2))`
`R_(2) = ((lambda_(2))/(lambda_(1)))^(2) xx R_(1) = 15.6 Omega`