<P> An electric "charge," such as a single electron in space, has an electric field surrounding it . In pictorial form, this electric field is shown as a dot, the charge, radiating "lines of flux ." These are called Gauss lines . Electric Flux Density is the amount of electric flux, the number of "lines," passing through a given area . Units are Gauss / square meter . Electric flux is proportional to the number of electric field lines going through a normally perpendicular surface . If the electric field is uniform, the electric flux passing through a surface of vector area S is </P> <Dl> <Dd> Φ E = E ⋅ S = E S cos ⁡ θ, (\ displaystyle \ Phi _ (E) = \ mathbf (E) \ cdot \ mathbf (S) = ES \ cos \ theta,) </Dd> </Dl> <Dd> Φ E = E ⋅ S = E S cos ⁡ θ, (\ displaystyle \ Phi _ (E) = \ mathbf (E) \ cdot \ mathbf (S) = ES \ cos \ theta,) </Dd> <P> where E is the electric field (having units of V / m), E is its magnitude, S is the area of the surface, and θ is the angle between the electric field lines and the normal (perpendicular) to S . </P>

Electric flux in an electric field e through area ds is given by