The torque on a bar magnet due to the earth's magnetic field is maximum when the axis of the magnet is

Draw the lines of force of a bar magnet neglecting the earth's magnetic field.

The earth's magnetic field may be considered to be due to a short magnet placed at the centre of the earth annd oriented along the magnetic south-north direction. The ratio of the magnitude of the magnetic field on the earth's magnetic equator to that at the magnetic poles is

A short bar magnet is placed along N-S direction with N pole pointing north. The neutral points are located 20 cm away from the bar magnet. If B_(H) is the horizontal component of earth's magnetic field then the magnetic field due to the bar magnet at distance of 40 cm along its axis is