Infinitesimal Electric field of slice of disk

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Homework Help Overview

The problem involves calculating the infinitesimal electric field produced by a circular slice of a uniformly charged disk with a given surface charge density. The context is rooted in electrostatics and the behavior of electric fields generated by charged objects.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to derive the electric field using equations related to uniformly charged rings and expresses uncertainty about the correct distance variable to use in their calculations. Some participants question the details of the original poster's approach and seek clarification on the provided lecture materials.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem and the original poster's approach. There is an emphasis on clarifying the use of variables and the application of lecture results, but no consensus has been reached yet.

Contextual Notes

There is a reference to a figure that is not visible in the thread, which may be crucial for understanding the problem setup. Additionally, the original poster expresses uncertainty about the definitions and assumptions related to the distance in their calculations.

j3dwards
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Homework Statement


A disk of radius R carries a uniform surface charge density σ.

(a) Using the results for the uniformly charged ring given in the lectures, or otherwise, compute the infinitesimal electric field dE due to the circular slice the disk of charge dQ shown in the figure. Express the result in terms of σ, r and R.

Homework Equations


E=kQ/d2

The Attempt at a Solution


qEx=kdQ/r2

dQ=σdA=2πσr dr

dr=R-r

dEx=σ(R-r)/2rεo

I'm not sure whether to put the distance d as x or just use the origin so just use r?

But when I used x as the distance, i couldn't put the answer in terms of σ, r and R. My workings for the use of x as the distance were:

dEx=k2πσxr/(r2+x2)3/2
 
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" ... shown in the figure. ..."??
 
rude man said:
" ... shown in the figure. ..."??
 

Attachments

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"Using the results for the uniformly charged ring given in the lectures, ... "
Are you doing this? What did they give you?
 

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