A dielectric in side a spherical shell

[FourierX]

Assume that there is a spherical dielectric inside spherical shell. There is a vacuum between the dielectric and the shell.

I found this configuration rather tricky. Any idea ?


http://img117.imageshack.us/img117/5901/conductorly3.th.jpg (http://img117.imageshack.us/my.php?image=conductorly3.jpg)


http://img117.imageshack.us/img117/7413/conductorwf9.jpg

[m.e.t.a.]

I'm not clear on your specific question. Could you elaborate?

[FourierX]

Consider the diagram above. Assume that the didelectric in the middle of shell contains charge Q. With this fact, how should the electric field be determined ?

[Defennder]

Why is this tricky? What can you say about the E-field from Gauss law?

[m.e.t.a.]

FourierX, there are a few "rules" that, if you are aware of them, will enable you to solve your problem:


The electric field outside of a uniformly charged sphere is the same as if all the charge were concentrated at its centre-point. This is true whether the sphere is hollow, solid, conductive or dielectric. This is also true of a hollow conductive shell which contains within its cavity any static arrangement of charges.
The electric field inside a hollow conductive shell is zero.
The electric field inside the body of a conductor is zero.


I would suggest that you have a try at deriving the above rules yourself. The maths is not difficult and your understanding will increase in the process. Best of luck.