State three characteristics of magnetic field lines
1) Magnetic field lines are continuous and form closed loops. This means that every magnetic field line originates from the north pole and terminates at the south pole of a magnet.
2) The density of magnetic field lines represents the strength of the magnetic field. Closer spacing of field lines indicates a stronger magnetic field, while wider spacing represents a weaker magnetic field.
3) The direction of magnetic field lines represents the direction in which a north pole of a compass needle would point when placed in the magnetic field. Field lines always move from the north pole to the south pole.