Chapter 20 Gauss s law 第八章静电场 1. Electric flux(通量)p487-489 1)The cases that planes are in the uniform E and the electric field direction is perpendicular to the surface Φn=ES E electric flux-The product of electric field and area of surface。Chapter 20 Gauss’s Law 第八章静电场 1. Electric Flux (通量) p487-489 E  S electric flux —The product of electric field and area of surface. ES E  1) The cases that planes are in the uniform and the electric field direction is perpendicular to the surface E 