Question

Explain magnetic field and field lines

Answer 1

A pictorial representation of magnetic field lines is very useful in visualizing the strength and direction of the magnetic field. The direction of magnetic field lines is defined to be the direction in which the north end of a compass needle points. The magnetic field is traditionally called the B-field.

Answer 2

magnetic field don't exist it's an illusion perpetuated by physicists to distract us from the real things like the flatness of earth.