Potential of a spherical shell (non-uniform charge density)

AI Thread Summary
The discussion focuses on calculating the electric potential and electric field of a spherical shell with a non-uniform surface charge density. Participants express confusion about the problem's requirements, particularly regarding the significance of charge density in the equations provided. There is a debate about the implications of having both positive and negative charges on the shell, which may lead to a net zero charge. Additionally, the challenge of determining the potential and field at various points in relation to the shell's surface is highlighted. The conversation emphasizes the need for clarity on how to approach the problem given the charge distribution.
SquidgyGuff
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Homework Statement


Given a spherical shell of radius R and the surface charge density
gif.gif
(
gif.gif
being the angle from the top of the sphere
gif.gif
and
gif.gif
being a constant) find the electric potential
gif.gif
and the electric field
gif.gif
inside and outside the sphere. Check that both the potential is continuous inside and outside the sphere and that
gif.gif
inside and out. I made this little diagram to illustrate.
sphere_by_k4l3b-d98wxw3.png


2. Homework Equations

gif.gif

gif.gif


The Attempt at a Solution


I can't even understand this problem. I feel like the point of interest shown in the diagram should be on the shell so that
gif.gif
can return a meaningful value, but I need to find the potential and electric field everywhere, so it can't be on the sphere.
 
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Hello Guff,

I notice that your problem statement mentions a charge distribution on the surface of the sphere, but that there is no equation where charge or charge density plays a role. Is there something you can add to your 'toolbox' ?
 
BvU said:
Hello Guff,

I notice that your problem statement mentions a charge distribution on the surface of the sphere, but that there is no equation where charge or charge density plays a role. Is there something you can add to your 'toolbox' ?
If I looked at the charge distribution a point charge the field would look like this
%5Cfrac%7B%28%5Csigma_%7B0%7Dcos%5Ctheta%29%284%5Cpi%20R%5E%7B2%7D%29%7D%7Br%5E2%7D%5Chat%7Br%7D.gif
, but I know that isn't correct because I believe the total charge is zero. because half of the values of
gif.gif
are negative and the other half are positive.
 
I still don't see how you want to find the field or the potential at a point in space.
Where exactly on the sphere is ##\cos\theta## negative ?
 
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