Question

Interactive Exercises 22.13: Electric Field Due to Two Charged Sheets: Sample Problem (Two Parallel Sheets of Charge) In an industrial process to large, thin, lat sheets of plastic are given uniform charges over their surfaces. The sheets are so large that, for locations not too close to the edges, we can approximate them as being in'inite in extent. Figure 22.13.1 shows a side view of the e o sheets, hich are pe al el. The +x r ns aleng one of the Sheets, and the axis s oerpencic er to both sheets. One sheet is ocated at v and the second sheet s located at v 4 m Sheet has area charge censity 6, where σ 5 n m and sect #2 hes area charge density- Ty Sheet 82 (Assumed infite y 2 n exeat Interactive Figurc 22.13.1: Side vicw ot two planar sheets with uniform area charge densitics. The sheets are approximated as infinite in cxtent, since the three ficld points, A, B, and G, are not close to the edges Question1 What is the net electric ficld (d ta both shets) at pcint A, which has coortinate yEnter a numerical value in the bax below. exact number, no tolerance Attempts: of 5 used Question 2 what is the net electric field (due to both sheets) at point B. ehich has coordinate y = 0? Enter a numerical veue in the box below. 1 NAC the tolerance |& +/-59h Attempts: 0 of 5 used Question 3 What is the nat electric field (d ta both sheats) at pcint C, which has caordinate y 3d/27 Enter a numarical value in the bax telaw. NNC exact number, no tolerance Attempts: o of 5 used

Answer 1

Field due to plate is constant and given by

$E=\frac{\sigma}{2\varepsilon_0}$

away from the sheet (for +ve and towards itself for -ve).

Thus, fields at point A and C, both are 0. Field at B is

$\vec E=\frac{\sigma}{2\varepsilon_0}\hat{\jmath}+\frac{\sigma}{2\varepsilon_0}\hat{\jmath}=\frac{\sigma}{\varepsilon_0}\hat{\jmath}$

Numerically,

$\vec E=\frac{25\times10^{-9}}{8.85\times10^{-12}}\hat{\jmath}=2.82\times10^3\textup{ V/m}$