A square frame of side `l` carries a current produces a field `B` at its centre. The same current is passed through a circular loop having same perimeter as the square. The field at its centre is `B'`, the ratio of `B//B'` is

Options

A. `(8sqrt(2))/(pi^(2))`
B. `(8)/(pi^(2))`
C. `(sqrt(2))/(pi^(2))`
D. `(pi^(2))/(8sqrt(2))`

Answer

1

Explanation

`B=4[(mu_(0))/(4pir)(sintheta_(1)+sintheta_(2))],B=(mu_(0)ni)/(2r)`