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.
- The orientation of area element decides the amount of electric flux. Thus, the area element is a vector.
- The vector associated with every area element of a closed surface is taken to be in the direction of the outward normal.
- Area element vector ΔS = ΔSn̂, ΔS is magnitude of area element and n̂ is unit vectorin the direction of outward normal.
- Electric flux, Δφ = EΔS = E ΔScosθ, θ is angle between E and ΔS.
- Unit of electric flux is NC-1m2.
- Total flux through a surface, φ ≈ Σ EΔS
