Question

The magnetic field at a point x on the axis of a small bar magnet is equal to the field at the point y on the equator of the same magnet the ratio of the distance of x and y from the centre of the magnet is

Answer 1

The shortest distance between the two poles of a bar magnet is the magnetic length of the bar magnet (2l). The axial line of a bar magnet is a straight line passing through its centre and its poles. The equatorial line of a bar magnet is a straight line perpendicular to its axial line and passing through its centre. The magnetic moment M of a magnet is defined as the product of its magnetic length 2l and its pole strength m. Therefore, M = 2lm. The SI unit of magnetic moment M is ampere metre-square (Am2) or weber metre (Wb.m). The magnetic moment of a bar magnet is a vector quantity whose direction is along its axial line, from its south pole towards its north pole.