Derive an expression for the magnetic induction at a point on the axial line of a bar magnet.

Explanation

Magnetic induction on the axial line of a bar magnet , is
` B = (mu_0)/( 4pi) (2Md)/((d^(2) -l^(2))^(2))`
In case of short bar magnet the magnetic indcution on the axial line is `B=(mu_0)/(4pi) (2M)/(d^(3))` .