If the moment of a magnet is `0.4 A-m^(2)` and force acting on each pole in a uniform magnetic field of induction `3.2 xx10^(-5) Wb//m^(2)` is `5.12 xx 10^(-5) N`, then find the distance between the poles of the magnet.

Explanation

Magnetic moment of the magnet , `M=0.4 A-m^2`
Magnetic field of induction , `B=3.2 xx 10^(-5)Wb // m^(2)`
Force acting on the each pole of the bar magnet ,
`F= 5.12 xx 10^(-5)N`
Pole strength of the magnet,
`m=(F)/(B) = (5.12 xx 10^(-5))/(3.2 xx 10^(-5)) = 1.6 A-m`
Distance between the poles of the magnet ( or ) length of the magnet , ` 2l = (M)/(m) = (0.4)/(1.6) = 0.25 m = 25 cm`