What is the magnitude of the equatorial and axial fields due to a bar manget of length `5*0cm` at a distance of `50cm` from its mid-point? The magnetic moment of the bar magnet is `0*40Am^2`.

Explanation

r = 50 cm = 0.5 m , M = `0.5 Am^(2)`
(i) Magnitude of equatorial field ,
`B_(E) = (mu_(0))/(4pi) . (M)/(r^(3)) = (4pi xx 10^(-7))/(4 pi) xx (0.4)/((0.5)^(3))`
(ii) Magnitude of axial field , Ba
`= (mu_(0))/(pi) . (2M)/(r^(3))`
`= 2 xx B_(E) = 2 xx 3.2 xx 10^(-7) = 6.4 xx 10^-7 T.`