The earth's field, it is claimed, roughly approximates the field due to a dipole to magnetic moment `8 xx 10^(22) J T^(-1)` located at its centre. Check the order of magnitude of this number in some way.

The earth's magnetic field at the equator is approximately 0.4G. Estimate the earth's dipole moment.

An electric dipole with dipole moment 4xx10^(9) Cm is aligned at 30^(@) with the direction of a uniform electric field of magnetude 5xx10^(4)NC^(-1) . Calculate the magnitude of the torque acting on the dipole.

The moment of a magnet is 1 muWb-m and the force acting on each pole in a uniform magnetic field of strength 0.38 oersted is 1.024xx10^(-4) N . Distance between the poles of the magnet is

A short bar magnet of magnetic moment 5.25 xx 10^(-2) JT^(-1) is placed with its axis perpendicular to the earth's field direction. At what distance from the centre of the magnet, the resultant field is inclined at 45^(@) with earth's field on (a) Its normal bisector and (b) its axis. Magnitude of the earth's field at the place is given to be 0.42 G. Ignore the length of the magnet in comparison to the distances involved.