Properties of magnetic lines of force (also known as magnetic field lines) are listed below:
1. Outside the magnet, the magnetic field lines are directed from N-pole of magnet towards S-pole. However, inside a magnet the field lines are directed from S-pole to N-pole. Thus magnetic field lines form a close loop.
2. The magnetic field line at any point points in the direction of magnetic field at that point.
3. The relative strength of magnetic fields is given by degree of closeness of the field lines. The magnetic field is strong in the region where the field lines are crowded.
4. No two magnetic field lines can ever intersect with each other.