Electromagnetism CheatSheet

Electric fieldcreated by a point charge:

The field is a vector that points outward ifis positive and inward ifis negative.

• For a system of charges:

Force between Point Charges

The forcebetween two point chargesandseparated by a distanceis given by:

whereis Coulomb’s constant andis the permittivity of free space.

Electric potentialdue to a point charge:

Potential due to Multiple Charges

Electric fluxthrough a closed surface:

whereis the charge enclosed by the surface.

Ampère’s Law (without displacement current):

whereis the enclosed current andis the permeability of free space.

Electromagnetic Induction

whereis the induced electromotive force (emf) andis the magnetic flux.

Magnetic fieldcreated by a chargemoving with velocity:

• For an infinite straight wire with current:

Force on a chargemoving in an electric and magnetic field:

1. Gauss’s Law for Electric Field:

2. Gauss’s Law for Magnetic Field:

3. Faraday’s Law of Induction:

4. Ampère-Maxwell Law:

Speed of lightin vacuum:

Wave equation for electric and magnetic fields