Question

What are magnetic field lines? Why two magnetic field lines can never intersect?

Answer 1

Magnetic field lines are the imaginary lines emerging from the north pole and merging at the south pole.

They do not intersect because if they do so it would mean that the compass would show two different directions at the point of intersection which is not possible

Answer 2

A magnetic field line is a curve in the magnetic field.If a compass is placed at any point on the field it points towards the field line.

Two magnetic field lines can never intersect because there can never be 2 directions of the field line at that point.