Chapter 15 & 16

Electrostatics: Forces & Energy

Electric Field Lines


Rules for Drawing Electric Field Lines
Electric field lines:

1. Point in the direction of the electric field vector at every point;

2. Start at positive (+) charges or at infinity;

3. End at negative (-) charges or at infinity;

4. Are more dense where has a greater magnitude. In particular, the number of lines entering or leaving a charge is proportional to the magnitude of the charge;

5. Lines of the net field never cross.


The electric field lines due to two positive charges of equal value.


The electric field lines due to a positive and a negative charge of equal value. Also known as a dipole.


On to Electric Field Lines Part 2