In
electromagnetism,
electric flux is the measure of flow of the
electric field through a given area. 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 is
where is the electric field (having units of ), is its magnitude, is the area of the surface, and is the angle between the electric field lines and the normal (perpendicular) to .