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

[somasimple]

"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

V_A = (k q₁ / r)
V_B = (k q₁ / r)

The Attempt at a Solution

V_AB = V_A - V_B = 0 V

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

 

[mfb]

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?

 

[somasimple]

That's right but its effect on voltage difference is the same as if there was no charge.

 

[voko]

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.