Charge Equality Between Different Size Pith Balls

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Discussion Overview

The discussion revolves around the behavior of electric charge distribution between pith balls of different sizes when they come into contact. Participants explore the implications of charge equality, charge density, and potential differences in relation to the geometry of the objects involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the charges would be equal if pith balls of different sizes come into contact.
  • Another participant suggests that if the charge density becomes uniform upon contact, the smaller ball would end up with less charge when separated.
  • A different participant explains that contact forces the potential of the balls to be the same, and that the ratio of charges would equal the ratio of their radii, assuming they are separated by a sufficient distance.
  • This same participant later questions whether the ratio of charges might instead relate to the cube of their radii, considering other geometries like disks or rods.

Areas of Agreement / Disagreement

Participants express differing views on how charge distribution occurs between pith balls of different sizes, with no consensus reached on the exact relationship between charge and size.

Contextual Notes

Participants mention assumptions regarding the uniformity of charge density and the influence of geometry, but these aspects remain unresolved within the discussion.

Who May Find This Useful

This discussion may be of interest to those studying electrostatics, particularly in relation to charge distribution and potential differences in conductive materials of varying geometries.

slickvic
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Suppose you let identical pith balls come in contact to make q1=q2. Would the charges be equal if the pith balls were of different size?
 
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You know, I vaguely remember doing this problem way back in freshman physics. Just a guess on my part, but I think that putting the balls in contact would make the charge density uniform. If my assumption is correct, then when you separate the balls, the smaller one would contain less charge.
 
I'm not real sure about pith, but I can answer for metal balls...

Putting the balls in contact forces their potential to be the same. The problem is easier if the balls are separated by a distance large compared to their size. Briefly connecting them with a wire would force the potential at each ball to be the same. In this case the ratio of charges would be equal to the ratio of the radii.
 
mdelisio said:
I'm not real sure about pith, but I can answer for metal balls...

Putting the balls in contact forces their potential to be the same. The problem is easier if the balls are separated by a distance large compared to their size. Briefly connecting them with a wire would force the potential at each ball to be the same. In this case the ratio of charges would be equal to the ratio of the radii.


Are you sure it wouldn't be equal to the ratio of the cube of their radii?

I'm asking because I'm also considering lesser dimensional problems. What if, instead of spheres, we were talking about disks, or straight rods? Well, maybe I should work the problem for myself and get back to you guys.
 

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