Question

A uniform isotropic dielectric is shaped as a spherical layer with radii a and b. Draw the approximate plots of the electric field strength E and the potential φ vs the distance r from the centre of the layer if the dielectric has a certain positive extraneous charge distributed uniformly: 

(a) over the internal surface of the layer; 

(b) over the volume of the layer.

Answer 1

(a) Positive extraneous charge is distributed uniformly over the internal surface layer. Let σ₀ be the surface density of the charge.

(b) Positive extraneous charge is distributed uniformly over the internal volume of the dielectric 

Let ρ₀ = Volume density of the charge in the dielectric, for a < r < b.