State four properties of magnetic field lines.

Explanation

Properties of magnetic field lines:
(i)The direction of the magnetic field is tangent to the field line at any point. Placing a small compass on the point points the direction of the field.
(ii) The strength of the field is proportional to the number of lines per unit area perpendicular to the lines.
(iii) Magnetic field lines do not cross each other.
(iv) Magnetic field lines are continuous, forming closed loops from the north pole to the south pole.