Question

why don't 2 magnetic lines of force intersect each other?​

Answer 1

if two magnetic field lines intersect each other at any point it means at that point of intersection there will be 2 directions of magnetic field lines qhich is not possible.

Answer 2

Consider that 2 magnetic field lines are intersected..

If they got intersected, there can be no lines passing through a definite point say for example, it got intersected at a place near north pole of the magnet, there can be no lines passing through north to south pole of magnet.

Hence, this is reason....