Question

When S-pole of the given bar magnet is placed on a table pointing geographical N-pole, where are the two null points located ?

• A. on the axial line at equal distance on either side
• B. on the equatorial line at equal distance on either side
• C. on the axial line only on one side of the magnet
• D. on the equatorial line only on one side of the magnet

Answer 1

Answer: (A)

on the axial line at equal distance on either side

The magnetic south pole of the earth's magnetic field is at the geographic north pole and the magnetic north pole is at the geographic south.
The magnetic field lines flow from north to south outside the magnet and south to north outside the magnet.
When the north pole of bar magnet points geographic south , the null points are formed on the axial line because magnetic field lines, from the bar magnet, directed north to south, are cancelled by the magnetic field lines due to the earth.