Show that a uniform magnetic field B cannot drop abruptly to zero (as is suggested by the lack of field lines to the right of point a in Figure) as one moves perpendicular to B, say along the horizontal arrow in the figure. In actual magnets, "fringing" of the magnetic field lines always occurs, which means that B approaches zero in a gradual manner. Modify the field lines in the figure to indicate a more realistic situation.

B N S