Solve Electrostatic Problem with Y.K.Lim Problem & Solutions

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Homework Help Overview

The discussion revolves around a problem from Y.K. Lim's "Problems and Solutions in Electromagnetism," specifically focusing on the expression for the electric field and its dependence on distance. Participants are examining the formulation of the electric field and questioning the presence of a square in the distance variable.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are exploring the nature of the electric field described, questioning the relationship between the electric field and distance, and discussing the implications of charge distributions versus point charges. There is also inquiry into the notation used, particularly regarding the unit vector e_r.

Discussion Status

The discussion is active, with participants providing insights into the nature of electric fields from charge distributions. Some express confusion over the notation and potential typos in the original problem statement, while others clarify concepts related to electric fields and their derivations.

Contextual Notes

Participants are navigating potential ambiguities in the problem statement, particularly regarding the mathematical representation of the electric field and the definitions of terms used. There is an acknowledgment of the possibility of typographical errors in the source material.

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Homework Statement



I'm looking at Y.K.Lim's Problems and solutions in Electromagnetism and there's one thing that's confusing me:

[PLAIN]http://img545.imageshack.us/img545/2218/capturegb.png

Homework Equations



Where does the square in r comes from? When in the beginning it says that the electric field is:

[tex]E=A\frac{e^{-br}}{r}e_r[/tex] not[tex]E=A\frac{e^{-br}}{r^2}e_r[/tex]

What am I missing?

And what should [tex]e_r[/tex] stand for? Charge?
 
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This E-field is not due to a single charge. It is due to a distribution of charges, so it needs not be proportional to r^2. For example, a uniformly charged plane produces uniform E-field on each side of the plane, obviously not proportional to distance^2, correct? :smile:
[tex]e_r[/tex] is the unit radius vector.
 
Ok it needs not be proportional to r^2, but why did he put it then? When taking the divergence of the field?
 
Oh I see. Then it seems to me that it's a typo :wink:
 
Oh, I thought it's something new I didn't know XD
 

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