Define magnetic field and magnetic field lines. Write down the properties of magnetic field lines.
Magnetic field: The region surrounding a magnet, in which the force of the magnet can be detected, is said to have a magnetic field. Magnetic field lines: Magnetic field lines are the imaginary lines drawn in a magnetic field along which a north magnetic pole would move. Properties of magnetic field line: Magnetic field lines are closed curves. The relative strength of the magnetic field is shown by degree of closeness of the field lines. No two field lines can cross each other as at the point of intersection the compass needle would point towards two directions, which is not possible.
