Electrostatic shielding in a cavity

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Discussion Overview

The discussion revolves around the concept of electrostatic shielding within a cavity, specifically examining the behavior of electric fields in the presence of an open lid conductor placed in a constant electric field. Participants explore whether the electric field in a marked area would be zero or equal to the original electric field, considering the implications of the conductor's open lid.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the electric field in the marked area would be zero when a conductor is placed in the electric field.
  • Others affirm that electric fields cancel out inside a conductor, suggesting this principle applies even with an open lid.
  • A participant questions whether the open lid affects the cancellation of the electric field, noting that charge accumulation could occur at the tips of the conductor.
  • Another participant argues that while the net electric field would approach zero near the bottom of the conductor, the open lid does matter in terms of field distribution.
  • One participant challenges the extension of the logic that any two conductors with an electrical path between them would have a nil electric field, using a hollow semi-sphere and a small sphere as a counterexample.
  • Some participants express uncertainty about the application of these principles in practical scenarios, such as the use of Faraday cages.

Areas of Agreement / Disagreement

Participants generally do not reach a consensus, as there are competing views regarding the effects of the open lid on the electric field and the applicability of electrostatic shielding principles to various conductor shapes.

Contextual Notes

The discussion includes assumptions about the behavior of electric fields in conductors and the specific configurations of conductors, which may not be universally applicable. The implications of the open lid on electric field behavior remain unresolved.

@bhishek
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Suppose a constant electric field exists in space as shown in the file and a open lid cube type conductor is brought inside the field. What would be the electric field in the question marked area. Would it be zero or equal to original electric field.
 

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Lid being open would slightly matter if it faced the electric field vectors, that the charge would accumulate on the tips and cause a curved electric field. The net electric field would still approach to zero as you got closer to the bottom. But in this case, it is definitely zero.
 
If that is the case than two conductors of any shape having an electrical path between them will have nil electric field between them when placed inside an electric field. Can we stretch the logic that far??
 
Not that far. Think of a hollow semi-sphere and a small sphere on its center, connected to it. When you apply an electric field in center to semi-sphere direction, there will be perpendicular fields between the end of the semi-sphere and the center, non-negligible.
 
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TESL@ said:
Not that far. Think of a hollow semi-sphere and a small sphere on its center, connected to it. When you apply an electric field in center to semi-sphere direction, there will be perpendicular fields between the end of the semi-sphere and the center, non-negligible.
Thank you,for explaining.
Is this type of shielding used anywhere?
 
  • #10
The regular Faraday cage is used but I don't know about the last device, I just made it up.
 
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  • #11
TESL@ said:
The regular Faraday cage is used but I don't know about the last device, I just made it up.
Thanks once again.
 

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