$A$ circular loop carrying a current is replaced by an equivalent magnetic dipole. $A$ point on the axis of the loop is

If a bar magnet of pole strength $m$ and magnetic moment $M$ is cut equally $5$ times parallel to its axis and again $3$ times perpendicular to its axis,then the pole strength and magnetic moment of each piece are respectively

$A$ steel wire of length $l$ and magnetic moment $M$ is bent into a semicircular arc of radius $R$. The new magnetic moment is

The distance between the poles of a horse shoe magnet is $0.1\, m$ and its pole strength is $0.01\, A\cdot m$. The induction of magnetic field at a point midway between the poles will be

$A$ magnetic needle is kept in a non-uniform magnetic field. It experiences

Write a brief history of magnets.