What is meant by the term magnetic field lines? List any two properties of magnetic field lines.

(N/A) Magnetic field lines are the imaginary paths or lines drawn in a magnetic field along which a free north pole would move if placed in that field.
Properties of magnetic field lines:
$(i)$ Magnetic field lines originate from the North Pole and merge at the South Pole outside the magnet.
$(ii)$ No two magnetic field lines intersect each other because if they did,there would be two directions of the magnetic field at the point of intersection,which is impossible.