Dipole above infnite conductor

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Discussion Overview

The discussion revolves around the behavior of an electric dipole positioned above an infinite conducting plane, specifically focusing on the mathematical representation of the dipole's potential and the resulting charge distribution. Participants explore the implications of their calculations and interpretations related to this electrostatic configuration.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant presents a formula for the electric potential and electric field derived from the dipole's image, questioning the interpretation of the resulting charge distribution.
  • Another participant expresses skepticism about the radial symmetry of the charge distribution, indicating a lack of clarity on the matter.
  • A participant questions the presence of a factor of 2 in the dipole moment expression, suggesting it may be an error.
  • Subsequent posts indicate that the participant who raised the factor of 2 acknowledges it as a mistake and expresses a desire to delete the thread due to confusion.
  • Another participant responds to the request for deletion, clarifying forum policy regarding thread deletion and expressing support for the original poster.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretation of the charge distribution or the presence of the factor of 2 in the dipole moment expression. There is ongoing uncertainty and debate regarding these points.

Contextual Notes

The discussion includes unresolved questions about the mathematical derivation and the assumptions underlying the dipole's behavior near the conductor, particularly concerning symmetry and the correctness of the expressions used.

OhNoYaDidn't
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An electric dipole p with arbitrary direction and is at distance a from plane infinite conductor at z=0.
Using the image of the dipole
##p=(2pcos\theta \hat{z}+psin\theta \hat{x}##
##p'=(2p'cos\theta \hat{z}-p'sin\theta \hat{x}##
220px-Image_of_dipole_in_plane.svg.png


Using the following:##V=\frac{\vec{p'}.\hat{r}}{4\pi\epsilon_0{r}^2}##, i get ## V=\frac{p'(2cos\theta-sin\theta)}{4\pi\epsilon_0{r}^2}## Which i can now write as ##\vec{E}## by symple taking the gradient in spherical coordinates. I get: ##\vec{E}=p'\frac{(2cos\theta-sin\theta)\hat{r}+(2sin\theta+cos\theta)\hat{\theta}}{4\pi\epsilon_0{r}^3}##
Now using one of Maxwell's laws i can get the charge distribution: ##\rho=\epsilon_0\nabla.\vec{E}=\frac{psin\theta}{4\pi{r}^4}## Does it make any sense that this is the result for charge distribution?
Thank you guys, I'm not really sure how to interpret this
 
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OhNoYaDidn't said:
Does it make any sense
Not to me. I don't see how it could be radially symmetric.
 
OhNoYaDidn't said:
An electric dipole p with arbitrary direction and is at distance a from plane infinite conductor at z=0.
##p=(2pcos\theta \hat{z}+psin\theta \hat{x}##
I do not understand where that 2 comes from.
 
I'm sorry, i wanted to edit my post, but somehow i can't :/. That 2 obviously shouldn't be there, it was a mistake when i was writing those in latex. I was doing the math again and i think i got it. If a moderator could delete this thread that would be good. Thank you anyway haruspex.
 
OhNoYaDidn't said:
I'm sorry, i wanted to edit my post, but somehow i can't :/. That 2 obviously shouldn't be there, it was a mistake when i was writing those in latex. I was doing the math again and i think i got it. If a moderator could delete this thread that would be good. Thank you anyway haruspex.
Glad you sorted it out. Don't onow why you could not edit the post... was there no "edit" button?
Forum policy is not to delete threads unless they violate some rule.
 

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