# A point charge inside a dielectric sphere

1. Apr 5, 2014

### eahaidar

Hello again
I seen in this forum about this problem but not in the special case when the point charge is at the center of the sphere how do I solve the series legendre polynomials?

2. Apr 5, 2014

### Staff: Mentor

This is a simpler version of the general problem - you can apply the general solution, but you can just use the symmetry and the usual laws for electric fields (what exactly do you want to calculate?).

3. Apr 5, 2014

### eahaidar

I need to solve the potential of a point charge in side a sphere of epsilon1 while outside with epsilon 2 if I use series solution I get r power over zero so I thought it's wrong any thoughts ??

4. Apr 5, 2014

### Staff: Mentor

Well r0 is just a constant.

You can simply use the symmetry and Gauß' law here.

5. Apr 5, 2014

### eahaidar

But usually if they have same epsilon okay I can find the image charge and then find the potential but what happens with different epsilon ?

6. Apr 6, 2014

### Staff: Mentor

You try to make this way too complicated... there is no need for any image charge.