Fux(通量)： =Fcos0de=E-d5 For a closed surface(Gauss surface) .=fE5 Electric flux through a surface is proportional to the number of electric field lines that pass through the surfaceFlux(通量):       S S e E d E dS   cos  For a closed surface( Gauss surface)     S e E dS   Electric flux through a surface is proportional to the number of electric field lines that pass through the surface