Question

Define magnetic field line​

Answer 1

Magnetic Field lines are the lines drawn in a magnetic field along which a north Magnetic pole would move. These lines are also called as the Magnetic lines of force. The lines of force is defined as a curve, the tangent to which at any point gives direction of force.

The intensity of the Magnetic field at any point in the magnetic field is the force experienced by a unit north pole placed at that point.