2d potential problem for a region bounded by 4 planes

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
3 replies · 2K views
samee
Messages
58
Reaction score
0

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?
 
Physics news on Phys.org
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?