Electric field lines
Electric field lines provide a means of visualizing the electric field. Since the electric field is a vector, electric field lines have arrows showing the direction of the electric field. As two examples, we show the electric field lines of a single point charge, and of a positive and negative charge.
The following rules apply to electric field lines:
Lines begin and end only at charges (beginning at + charges, ending at - charges) or at Infinity.
Lines are closer together where the field is stronger.
Larger charges have more field lines beginning or ending on them.
Electric Field lines never cross (since E must point in a definite direction unless it is zero).
For instance, the positive charge is stronger than the negative charge on the upper right diagram, since there are more lines originating from the positive charge and the lines from the negative charge are more strongly bent than the lines from the positive charge.