# Homework Help: Hollow dielectric sphere

1. Mar 7, 2009

### -EquinoX-

1. The problem statement, all variables and given/known data
I am asked to find if there exists an electric field of a hollow dielectric field at a sphere is 0 and proof it.

2. Relevant equations

3. The attempt at a solution
I've drawn this picture:

http://img19.imageshack.us/img19/2295/hollowp.th.jpg [Broken]

$$\omega \rightarrow 0$$
$$\delta q \rightarrow dq \rightarrow 0$$

$$E1 = k \frac{dq1}{r1^2}$$
$$E2 = k \frac{dq2}{r2^2}$$

if $$\vec{E_1} + \vec{E_2} = \vec{0}$$ for p
$$\vec{E_net} = \vec{0}$$for all p
$$k \frac{dq_1}{r_1^2} = \frac{k\sigma\dA_1}{r_1^2}$$
$$k \frac{dq_2}{r_1^2} = \frac{k\sigma\dA_2}{r_2^2}$$

Explanation of the picture:
1. The two dotted circles are gaussian sphere each with radius r1 and r2.
2. The solid circle is the hollow dielectric sphere viewed from one side
3. P is just a point inside the dielectric sphere

So far this is all I got, can someone please guide me what to do next in this proof..

Last edited by a moderator: May 4, 2017
2. Mar 8, 2009

anyone?