Dielectric and force between charges

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Homework Help Overview

The discussion revolves around the force between two point charges placed at specific positions along the x-axis, particularly when a dielectric material is introduced between them. The original poster presents a scenario where the force is calculated without the dielectric and questions how the presence of the dielectric affects this force.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of inserting a dielectric on the force between the charges, with some suggesting that the force remains unchanged. Others question the behavior of the electric field and the displacement field in the presence of the dielectric, particularly at the boundaries.

Discussion Status

There is an ongoing exploration of the effects of the dielectric on the force between the charges. Some participants express uncertainty about the implications of the dielectric on the electric field and force calculations, while others seek clarification on the behavior at the dielectric boundary.

Contextual Notes

Participants note that the dielectric only occupies a specific region between the charges, raising questions about how this localized presence affects the overall force experienced by the charges. There is also mention of the relationship between the electric field and the displacement field in the context of dielectrics.

shomey
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Homework Statement

suppose I have a charge q at (x=-d) and a charge q at (x=+d).
the force between them is q^2/(4*pi*(eps_0)*4*d^2).

now, I insert a dielectric (K) between (-d/2<x<d/2), what would be the force between the charges now?



The attempt at a solution

it seems like it would be the same but it sounds strange...
If I use the D field, it is not effected by the dielectrics, and thus I can see that the electrical field E is the same as before (D/eps_0) and thus the force is the same...

could it be?
 
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shomey said:
Homework Statement

suppose I have a charge q at (x=-d) and a charge q at (x=+d).
the force between them is q^2/(4*pi*(eps_0)*4*d^2).

now, I insert a dielectric (K) between (-d/2<x<d/2), what would be the force between the charges now?



The attempt at a solution

it seems like it would be the same but it sounds strange...
If I use the D field, it is not effected by the dielectrics, and thus I can see that the electrical field E is the same as before (D/eps_0) and thus the force is the same...

could it be?


someone?? please?
I really need help with this...
 
F=qE and E=D/(K*epsilonzero)
 
pam said:
F=qE and E=D/(K*epsilonzero)

that's just it, i don't think this is it.
notice that the two charge are in the matter eps_0.

* the other dielectric is only found at (-d/2 < x < d/2 ).
* the two charges are in (x = -d) and (x = +d).

so it seems like the force will be F=qE and E=d/eps_0.
which is exactly like if there was no dielectric between them, and it seems pretty weird to me...
 
What happens at the dielectric surface/boundary?
Regards,
Reilly Atkinson
 

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