The field due to a wire of n turns and radius r which carries a current I is measure on the axis of the coil at a small distance h form the centre of the coil. This is smaller than the field at the centre by the fraction:

Options

A. `3/2 ( h^2)/(r^2)`
B. `2/3 (h^2)/( r^2)`
C. `3/2 (r^2)/(h^2)`
D. `2/3 (r^2)/(h^3)`

Answer

A