The magnetic field at the centre of a circular current carrying coil of radius r is `B^(e )`. The magnetic on its axis at a distance r from the centre is `B_(a)`. The value of `B_(e) : B_(a)` will be :

Options

A. 1 : `sqrt2`
B. 1 : `2sqrt2`
C. `2sqrt2` : 1
D. `sqrt2` : 1

Answer

3

Explanation

(B_(e))/(B_(e))=((R^(2)+x^(2))/R^(2))^(3//2)=((R^(2)+R^(2))/R^(2))^(3//2)=2sqrt2`