Electric field vs. Electric potential

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Homework Help Overview

The discussion revolves around the relationship between electric field and electric potential, specifically focusing on the equation V(r) = V(o) r^2/2R^2. The original poster seeks assistance in finding E(r) given that R and V(o) are constants.

Discussion Character

  • Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to understand how to derive the electric field E from the given potential V, expressing uncertainty about the need for integration. Some participants clarify that differentiation is required instead of integration.

Discussion Status

The discussion is active, with participants providing guidance on the differentiation process needed to find E from V. There is an acknowledgment of the original poster's difficulties with math, and some participants are addressing these concerns by clarifying the steps involved.

Contextual Notes

The original poster mentions a lack of recent math study, which may affect their understanding of the concepts being discussed. This context highlights the challenges faced in grasping the mathematical aspects of the problem.

wave41
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Hello everyone...I need help to start on a problem which states that V(r) =V(o) r^2/2R^2...I neeed to find E(r) when R and V(o) are constants...so from defention E= dV/Dr? This is the part I am not sure how to move on..I have to integrate the equation they gave me keeping the V(o) and R as constants?
Thank you...
 
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[tex]E = \frac{d}{dr}V(r)[/tex]

V(r) is given, so you get

[tex]E = \frac{d}{dr}\left(V_0 \frac{r^2}{2R^2} \right)[/tex]

So what's the problem?

cookiemonster
 
The problem is that I have a very bad math backround...I am asking if I have to integrate that? Keeping V(o) and R outside the integral...I have not done integrals yet so I am having trouble with it...I have missed math (meaning didn't study it ) from basically 4th grade to 9th so to catch up on it takes me a while...
 
E is defined as the derivative of V. You have V. You'd then have to differentiate V to get E.

There are no integrals involved.

Now, if you had E and you were asked to find V, then you'd have to integrate. But it's the other way around, hence differentiate.

The problem is asking you to evaluate the derivative I described above.

cookiemonster
 
thank you :smile:
 

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