Chapter 19.2, Problem 2dTH

Consider the left side of the box as Consisting of N small pieces. Let ${\stackrel{\to }{dA}}_i$ represent the area of the $i^{th}$ small surface element on the left side of the box, and let ${\stackrel{\to }{E}}_i$ , represent the electric field on that surface element.

Write an expression for the net electric flux ${\Phi }_{\text{net}}$ through the left side of the box in terms of ${\stackrel{\to }{dA}}_i$ and ${\stackrel{\to }{E}}_i$ .