What is the Electric Field in a Non-Uniformly Charged Spherical Volume?

AI Thread Summary
The discussion revolves around a challenging exam question regarding the electric field in a non-uniformly charged spherical volume, specifically with a charge density that increases with distance from the center. The charge density is given as a function of distance, expressed as (5.5*10^-15)*r^2.3. Students are struggling to understand the calculations provided by the professor and are seeking clarification and guidance on how to approach the problem, particularly regarding the use of integrals. The confusion stems from the non-standard power of the radius in the charge density equation. Overall, the participants express frustration and a desire for assistance in solving the problem.
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I have an exam on Monday in my E&M class. I've been doing the homework, etc etc. My prof. even has a link on his website that has old exams that we can use to study from. The exam I am practicing off of has the questions, a (sketchy) calculation, and an answer. This question has been driving me and my classmates NUTS! Nobody can solve it! I can't make sense of his calculations, can somebody please tell me I am not crazy…or, better yet…show me what I am not seeing. Thanks.

ScreenShot2011-09-17at114319PM.png


That weird looking thing at the top that looks like R**(2.3) is supposed to be the radius to the power of 2.3. Yeah, I don't get it either, but that's what my prof. told me.

The answer is in parenthesis.

Is there something wrong with the calculations?

Why can't I figure this out??
 
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Rewriting this, in case you don't understand it: you have a spherical volume filled with distributed static charge. It's not uniformly distributed, it gets more dense the farther you move away from the centre. The charge density in the sphere is a function of distance from the centre=(5.5*10-15)*r2.3

I've forgotten how to solve these. :redface: I guess it's going to involve an integral.
 
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