2d potential problem for a region bounded by 4 planes

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Homework Help Overview

The discussion revolves around a 2D potential problem defined within a region bounded by four planes, with specific boundary conditions for the electrostatic potential. The problem involves solving Laplace's equation in two dimensions, given that there are no charges present in the region.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the setup of the problem and express uncertainty about how to approach solving Laplace's equation. There are attempts to clarify the form of Laplace's equation and its relation to the boundary conditions provided. Some participants question the interpretation of the equation derived from the potential function.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem and attempting to clarify the mathematical relationships involved. Some guidance has been offered regarding the need to write down the general form of Laplace's equation and consider the boundary values.

Contextual Notes

Participants note that the problem involves specific boundary conditions at the planes, which are crucial for solving the Laplace equation. There is an emphasis on the absence of charges within the bounded region, which influences the formulation of the problem.

samee
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Homework Statement


Consider a 2d potential problem for a region bound by 4 planes
x=-1/2
x=1/2
y=0
y=1

There are no charges inside the bounded region. The boundaries at y=0 and y=1 are held at zero potential. The potential at the boundaries x=-1/2 and x=1/2 is given by,
V(-1/2,y)=V(1/2,y)=Vosin(2piy)

(a) Find the electrostatic potential V(x,y) everywhere inside this region by solving the Laplace equation in 2 dimensions using the method of separation of variables.
(b) Calculate the surface charge density on the boundary y=0


Homework Equations


V(-1/2,y)=V(1/2,y)=Vosin(2piy)


The Attempt at a Solution


Okay, so I know that the potential is an integral, but it seems unsolvable to me! Help me at least set up this problem so I can go from there?
 
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The question explicitly mentions Laplace's equation. How does it look like?
If you have it, try solving it using the hint in the question.
The boundary values will enable you to write the potential everywhere.
 
so,
dVosin(2piy)2 = 0
d2x

dVosin(2piy)2 = 2piVocos(2piy)
d2y

dVosin(2piy)2 = 0
d2z

So then the laplace equation is 0+2piVocos(2piy)+0=2piVocos(2piy)

But this isn't an integral so it can't be V, can it?
 
No, this only looks similar to Laplace's equation.
It will be a differential equation relation the potential to the charge density (zero here). Every differential equation needs some initial or boundary values. Here the boundary values are given by the value of the potential on the four planes.
Why don't you write down the general Laplace equation as you learned it in the course?
 

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