Electric flux 

1. Electric flux (Φ_E) linked with a surface (flat or curved) gives us an idea of the total number of electric field lines passing normally through that surface.

2. Electric flux is defined as the surface integral of the electric field inked with that surface i.e.

Here θ is the angle between electric field vector & area vector ( i.e. an area vector conventionally directed normally outwards to the area under consideration).

3. SI unit of flux: Weber (Wb)

4. CGS unit of flux: Maxwell (Mx)

5. Conversion: 1Wb = 10 ⁸ Maxwell = 1Vm

6. Being dot product, electric flux is a scalar quantity.

7. Maximum value of flux = ± E S

8. Minimum value of flux = 0 (when θ = π/2)

9. If θ is acute flux is + ve & called leaving.

10. If θ is obtuse flux is – ve & called entering.