Point Charge in a Dielectric Sphere

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 reply · 8K views
KeyToMyFire
Messages
6
Reaction score
0

Homework Statement



A point charge q is located at the center of a dielectric sphere of radius a. Find D, E, and P everywhere and plot your results. What is the total bound charge on the surface of the sphere?

(I assume by "everywhere" my professor meant inside and outside the sphere.)
(D is the electric displacement)

Homework Equations



[itex]\nabla[/itex][itex]\cdot[/itex](ε0E+P)=ρf

and

D[itex]\cdot[/itex]da=qwhere the integral is over the closed surface and ρf is the charge density of the enclosed free charge.

The Attempt at a Solution



Using that, I got D=(q/4[itex]\pi[/itex]r2)[itex]\hat{r}[/itex]

And that Er>a= (1/ε0)D

Beyond that (if that is even correct), I feel like I need more information (or I have no idea what I'm doing).
 
Physics news on Phys.org
Looks good so far. To go further, maybe you are supposed to assume the material has a certain dielectric constant Ke. So, D = KeεoE. Then you can express your answers for P and E in terms of Ke.