How Does Electric Flux Represent The Field Lines ?
Electric flux over an area in an electric field represents the total number of field lines crossing this area. We know that the number of field lines crossing a unit area placed normal to the field at a point is a measure of strength of electric field E at that point. If we place a small planar element of area ∆S normal to E at this point, number of electric filed lines crossing this area element is proportional to E (∆S) note that it is not proper to say that number of field lines crossing the area is equal to E (∆S). The number of field lines is after all a matter of how many field lines we choose to draw. What is physically significant is the relative number of field lines crossing a given area at different points. If we tilt the area element by angle θ [or we tilt E w. area element by angle θ, the number of field lines crossing the area will be smaller. As projection of area element normal to E is ∆S cos θ (or component of E normal of electric filed lines crossing area ∆S is proportional to E∆S cos θ.
