# Dielectric sphere in point charge electric field

1. May 24, 2010

### paweld

I'm interested if it's possible to compute potential inside and outside
dielectric sphere (with permittivity $$\varepsilon_1$$) which is
placed in field of point charge q lying outside the sphere where
permittivity is $$\varepsilon_2$$. I've tried to solve it
using Legendre polynomilas but I obtain infinite sum which
I cannot interpretate as images (maybe I made a mistake).
So this problem cannot be solve using methods of images???

2. May 24, 2010

### clem

Images won't work. Your LP sum is the standard solution.

3. May 25, 2010

### DrDu

Images work, but there are infinitly many of them!

4. May 25, 2010

### paweld

Thanks for answers. It's quite strange that such apparently simple
problem has only solution in terms of infinite sum.

5. May 25, 2010

### Meir Achuz

sin x is also calculated by an infinite sum.

6. May 25, 2010

### paweld

indeed, for computer it doesn't matter