1. Equipotential surfaces
Electric Fields
Coulomb’s law
The electric field
Electric field lines
Electric potential
Equipotential surfaces

2. Coulomb’s Law The SI unit of charge is the coulomb (C)
ke is called the Coulomb constant
ke = x 109 N.m2/C2 = 1/(4πo)
o is the permittivity of free space
o = x C2 / N.m2

3. The electric field
The electric field vector, E, at a point in space is defined as the electric force F acting on a positive test charge, qo placed at that point divided by the test charge: E = Fe / qo

4. Electric field lines

5. Electric potential The electric potential is
The potential is a scalar quantity
Since energy is a scalar
As a charged particle moves in an electric field, it will experience a change in potential

6. Equipotential Surfaces
The equipotential surfaces must always be perpendicular to the electric field lines passing through them.
A point charge
An electric dipole
Infinite sheet of charge