from north pole and merge at the south pole (note the arrows marked on the field lines in Fig. . ). Inside the magnet, the direction of field lines is from its south pole to its north pole.
Thus the magnetic field lines are closed curves. The relative strength of the magnetic field is shown by the degree of closeness of the field lines. The field is stronger, that is, the force acting on the pole of another magnet placed is greater where the field lines are crowded (see Fig. .
). No two field-lines are found to cross each other. If they did, it would mean that at the point of intersection, the compass needle would point towards two directions, which is not possible.