The magnetic dipole moment of a short magnetic dipole at a distant point along the equator of magnet has a magnitude of ' $X$ ' in SI units. If the distance between the point and the magnet is halved then the magnitude of dipole moment will be

Two parallel conductors carrying unequal currents in the same direction ............

The magnitude of the magnetic induction at a point on the axis at a large distance ( $r$ ) from the centre of a circular coil of ' $n$ ' turns and area ' $A$ ' carrying current ( $I$ ) is given by