电场线的性质

Electric field lines have specific properties.

In the presence of a positive charge, the field lines originate on it and extend to infinity. For a negative charge, they come in from infinity and culminate on it, indicating the force a positive test charge would experience in its vicinity.

Since the field of a charge is directly proportional to its magnitude, the number of field lines is also proportional to it.

The electric field is always tangential to the electric field line.

Field lines can never cross. If they did, it would imply two different directions of the field, which is impossible.

For a pair of positive charges of the same magnitude, the field lines originate from each and extend to infinity. In between, they point opposite to each other and effectively cancel, implying the electric field is small or zero.

In a dipole, the field lines of the negative charge are reversed, thus reinforcing the field lines in that region.

A constant field is represented by straight, parallel, and uniformly spaced field lines.