Electric Flux- Basics to Advanced level

What exactly is electric flux?

In this course, we will look at the notion of electric flux, how to calculate it, and how the flux of an electric field compares to that of water. Consider the flow of water in a pipe with a velocity v in a fixed direction, say to the right. If we examine a tiny unit area provided by ds from the pipe's cross-sectional plane, the volumetric flow of the liquid traversing that plane normal to the flow may be represented as vds. When the plane is not perpendicular to the fluid flow but is slanted at an angle, Here, ds cosθ is the projected area in the plane perpendicular to the flow of the liquid.

The electric field is analogous to the liquid flow in the case shown above. The quantity we will deal with here is not an observable quantity as the liquid we considered above.

Electric Flux Formula

The total number of electric field lines passing a given area in a unit of time is defined as the electric flux. While the electric flux is not affected by charges that are not within the closed surface, the net electric field, E can be affected by charges that lie outside the closed surface. While Gauss's law holds for all situations, it is most useful for "by hand" calculations when high degrees of symmetry exist in the electric field. Examples include spherical and cylindrical symmetry.

The SI unit of electric flux is the volt-meter (V·m), or, equivalently, the newton-meter squared per coulomb (N·m2·C−1). Thus, the unit of electric flux expressed in terms of SI base units is kg·m3·s−3·A−1.