Caption: An animation illustrating how field lines are are generated for a vector field.
Features:
A field line points in the direction of the vector field: i.e., NOT opposite the direction of the vector field.
However, in a diagram, a vector field can only be represented by a finite discrete set of representive arrows →.
Similarly, field lines form continuum and can only be represented in a diagram by a representative set of curves.
However, in certain cases they do have a physical meaning: