A bar magnet is `0.10` m long and its pole strength is 120 Am . Find magnitude of magnetic field at a point on its axis at a distance 20 cm from it .

Explanation

`B_("axial") = (mu_(0))/(4pi) (2 M xx r)/((r^(2) - l^(2))^(2))`
`= (10^(-7) xx 2xx (120 xx 0.1) xx 0.2)/([(0.2)^(2) - (0.05)^(2)]^(2))`
`= 3.4 xx 10^(-5) T`