What are magnetic field lines : Justify the following statements.
(a) Two magnetic field lines never interesect each other.
(b) Magnetic field lines are closed curves.

Explanation

Magnetic field lines. It is defined as the path along which the unit North pole (imaginary) tends to move in a magnectic field if free to do so .
(a) The magnetic lines of force do not intersect (or cross ) one another . If they do so then at the point of intersection, two tangents can be drawn at that point which indicates that there will be two different directions of the same magnetic field. i.e. the compass need points in two different directions which is not possible .
Magnetic field lines closed continuous curves. They diverge from the north pole of a bar magnet and converge is south pole. Inside the magent they move from south pole to north pole.