What is the Surface Charge Density for a Spherical Cavity?

AI Thread Summary
To find the surface charge density of a spherical cavity with an excess charge of 1.5 x 10^-7 Coulombs, the formula used is charge divided by the area of the inner sphere. The area of the inner surface can be calculated using the formula for the surface area of a sphere, which is 4πr², where r is the inner radius of 1.5 cm. There is confusion regarding whether the sphere is a conductor or an insulator; if it is a conductor, the inner surface would have no charge. Clarification on the material properties of the sphere is necessary to proceed with the calculation. Understanding these concepts is crucial for solving the problem effectively.
Clancy
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Homework Statement



A sphere with excess charge of 1.5 x10 -7 Coulombs, An outer radius of 2.5cm and inner radius of 1.5 cm ( a cavity ). The question is to find the surface charge density on the inside surface.

I'm totally at a loss on this one and couldn't find how to solve it.

Homework Equations



Well surface charge density would be C/area of inner sphere.

The Attempt at a Solution



I couldn't at all figure out how this is done and didnt fiond anythig on it in HRW any help please?
 
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If the sphere is made of good conductor, there will be no charge on the inner surface of the sphere.
 
Is this an insulating sphere or a conducting sphere?
 

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