The ratio of magnetic fields on the axis of a cricular current cerrying coil of radius a to the magnetic field at its centre lying on the periphery of the surface of the sphere will be .

Options

A. `(1)/((1+(x^(2))/(a^(2)))^(3//2))`
B. `(1)/((1+(a^(2))/(x^(2)))^(1//2))`
C. `(1)/((1+(a^(2))/(x^(2)))^(2))`
D. `(1)/((1+(a^(2))/(x^(2)))^(3))`

Answer

A