Write any three properties of magnetic field lines.

Explanation

Properties of magnetic lines of force (also known as magnetic field lines) are listed below :
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
The magnetic field line at any point, points in the direction of magnetic field at the point
The relative strength of magenetic 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.
No two magnetic field lines can ever intersect with each other.