Chapter 21, Problem 54P

(III) Uniform plane of charge. Charge is distributed uniformly over a large square plane of side ℓ, as shown in Fig. 21–68. The charge per unit area (C/m²) is σ. Determine the electric field at a point Ρ a distance z above the center of the plane, in the limit ℓ → ∞. [Hint: Divide the plane into long narrow strips of width dy, and use the result of Example 21–11; then sum the fields due to each strip to get the total field at P.]

FIGURE 21–68

Problem 54.