For a point charge q at position (i.e., an electric monopole), the electric field at a point r is defined in cgs to be
In MKS, the corresponding equation is
where is a fundamental constant called the permittivity of free space. The electric field is therefore defined such that for an electric monopole, E points away from a positive charge and towards a negative charge.
D, Electric Dipole, Electric Monopole, Electric Multipole Expansion, Electromagnetic Field, Electromagnetic Field Tensor, Electromagnetic Wave, Magnetic Field, Maxwell Equations, Infinite Plane, Infinite Parallel Planes, Sphere Electric Field
References
Griffiths, D. J. Introduction to Electrodynamics, 3rd ed. Englewood Cliffs, NJ: Prentice-Hall, 1998.
