Charge Distribution on Conducting Spherical Shell

[pyroknife]

Homework Statement

A conducting spherical shell that has zero net charge has an inner radius R1 and an outer radius R2. A positive point charge q is placed at the center of the cell. The 1st part was to find the electric fields at the 3 diff places. The part I need help on is where we have to find the charge density on inner surface r=R1 and outer surface r=R2.

what I have a question about is. The signs would be opposite for inner and outer. Is the one entering (inner surface) negative and the one leaving (outer surface) positive? If so, why is it like that?

 

[ehild]

what I have a question about is. The signs would be opposite for inner and outer. Is the one entering (inner surface) negative and the one leaving (outer surface) positive? If so, why is it like that?

There is a positive charge at the centre. Does it attract or repel the free electrons in the metal shell? So what kind of excess charge accumulates at the inner surface of the shell?


ehild