Invisible Charge: Solving for Equal Distance in Coulomb's Law

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Homework Help Overview

The discussion revolves around a problem related to Coulomb's Law and electric potential, specifically examining the implications of a charge being at equal distances from two points, A and B. Participants explore the concept of electric potential and its relationship to charge visibility.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the implications of equal distances in terms of electric potential, questioning whether this leads to the charge being "invisible." They explore analogies with gravitational potential and equipotential surfaces to clarify their reasoning.

Discussion Status

The discussion is active, with participants providing differing perspectives on the visibility of charge and the nature of electric potential. Some have offered analogies to aid understanding, while others are questioning the assumptions behind the original poster's statement.

Contextual Notes

Participants are navigating the nuances of electric potential and charge configurations, with references to specific equations and concepts from Coulomb's Law. The original poster's use of the term "invisible" charge is under scrutiny, prompting further exploration of the definitions and implications involved.

somasimple
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"Invisible" charge?

HI all,

Homework Statement


https://www.physicsforums.com/showthread.php?t=427862
See attached picture. q1 is at equal distance from A or B.
k = coulomb's constant

Homework Equations



VA = (k q1 / r)
VB = (k q1 / r)

The Attempt at a Solution



VAB = VA - VB = 0 V

It seems that the charge becomes invisible in that case, right?
 

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The charge is not invisible.

We have (roughly) the same gravitational potential everywhere on the surface of earth. Is Earth invisible? Do you float freely in space?
 
That's right but its effect on voltage difference is the same as if there was no charge.
 
Any charge configuration admits equipotential surfaces. The potential difference between any two points on such a surface is zero. Which does not mean there is no charge.
 

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