Calculate magnetic field due to a bar magnet 2 cm long having pole strength 100 Am at a point 20 cm from centre of bar magnet .
(i) On axial point `" "` (ii) On normal bisector

Explanation

(i) ` B = (mu_(0))/(4pi) (2 M)/(r^(3))`
`M = q_(m) xx L`
`= 100 xx 2 xx 10^(-2) Am^(2)`
`= 100 xx 2 xx 10^(-2) Am^(2)`
`= 2 Am^(2)`
B = `10^(-7) xx (2 xx 2)/((0.2)^(3))`
`= 10^(-7) xx (4)/(8 xx 10^(-3))`
`= 0.5 xx 10^(-4)`
`= 5 xx 10^(-5) T`
(ii) B = `(mu_(0))/(4pi) (M)/(r^(3))`
B = `10^(-7) xx (2)/((0.2)^(3))`
`=2.5 xx 10^(-5) T`