The work done in twisting a steel wire of length 25cm and radius 2mm through `45^(@)` will be `(eta=8xx10^(10)N//m^(2))`

Options

A. `2.48J`
B. `3.1J`
C. `15.47J`
D. `18.79J`

Answer

A

Explanation

`W=(1)/(2)Ctheta^(2)=(pietar^(4)theta^(2))/(4l)=(3.14xx8xx10^(10)xx(2xx10^(-3))^(4)xx(pi//4)^(2))/(4xx25xx10^(-2))=2.48"J"`