What Are the Assumptions and Calculations for Sheet of Charge Theory?

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SUMMARY

The discussion focuses on the assumptions and calculations related to the Sheet of Charge Theory in electrostatics. It clarifies that when the thickness of a plate is not specified, it is considered infinitely thin for practical calculations. The area in the formula σ=Q/A accounts for the total surface area of both sides of the sheet when calculating surface charge density. In scenarios involving parallel plates of opposite charge, the area used in Gaussian surface calculations should reflect the side where the charge resides, not halved. Charge distribution occurs on the outer surface of conductors, emphasizing the importance of surface area over volume in capacitor charge distribution.

PREREQUISITES
  • Understanding of electrostatics principles
  • Familiarity with the concept of surface charge density (σ)
  • Knowledge of Gaussian surfaces in electrostatics
  • Basic concepts of capacitors and charge distribution
NEXT STEPS
  • Study the derivation of the electric field due to an infinite sheet of charge
  • Learn about the application of Gauss's Law in electrostatics
  • Explore the behavior of electric fields between parallel plates of capacitors
  • Investigate the effects of charge distribution on different geometries of conductors
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Students and professionals in physics, electrical engineering, and anyone studying electrostatics and charge distribution in capacitors and conductive materials.

Iamconfused123
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Homework Statement
..
Relevant Equations
EA=Q/Eo, Sigma=Q/A, E=kQ/r^2
To some of these questions I can't find answers on the internet and to some I assume what the answer is but I'd still like to get a confirmation.


When I am not given the thickness of the plate, does that mean that the plate is intinitely thin?


What is the area of the sheet of charge when the sheet stands alone when we calculate sigma=Q/A, is it the surface area of both sides of the sheet or just one side?


What is the area in sigma=Q/A when we have a plate next to another parallel plate of opposite charge ( I assume for this one area to be only one side, but still)? In this case what area do we put in formla for Gaussian surface (EA=Q/Eo), because when two plates of opposite charges are next to each other then positive and negative charges on the same plate separate and the extra (for example of positive charge) eminate field only to the right, for example (or do they, I am not sure about this one), so should the area of the Gaussian surface be halved as well?


How does charge distribute itself over infinitely thin sheet? Is area for sigma=Q/A here only one side or both sides?


If charge does not reside IN the conductor but only on the outer surface, do we take only the surace area into account for charge distribution of the capacitor or do we care about volume?



Thank you very much.
 
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Iamconfused123 said:
When I am not given the thickness of the plate, does that mean that the plate is intinitely thin?
Either arbitrarily thin or, for the question asked, the thickness won't matter.
Iamconfused123 said:
What is the area of the sheet of charge when the sheet stands alone when we calculate sigma=Q/A, is it the surface area of both sides of the sheet or just one side?
If Q is the whole charge and ##\sigma## is the density on each side then A is the total area for the two sides.
Iamconfused123 said:
What is the area in sigma=Q/A when we have a plate next to another parallel plate of opposite charge ( I assume for this one area to be only one side, but still)?
If the arrangement ensures all the charge is on the same side then clearly A is just the area of that side.
Iamconfused123 said:
In this case what area do we put in formla for Gaussian surface (EA=Q/Eo), because when two plates of opposite charges are next to each other then positive and negative charges on the same plate separate and the extra (for example of positive charge) eminate field only to the right, for example (or do they, I am not sure about this one), so should the area of the Gaussian surface be halved as well?
I'm not sure I have understood the situation. Please give a specific example.
Iamconfused123 said:
How does charge distribute itself over infinitely thin sheet? Is area for sigma=Q/A here only one side or both sides?
No sheet is infinitely thin. It can be arbitrarily thin.
Iamconfused123 said:
If charge does not reside IN the conductor but only on the outer surface, do we take only the surace area into account for charge distribution of the capacitor or do we care about volume?
Not volume, which would be the product of surface area and plate separation. Instead, it is the ratio of the two that matters.
 

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