Finding the potential of a conducting disk(without laplace)

In summary, a conducting disk in space can be found by integrating the potential of a uniformly charged rod. The disk is an ellipsoid in the limit that its z length is zero. The method for finding the potential of a disk is much simpler than the method for finding the potential of a rod, but it is still a difficult problem.
  • #1
sentinel
18
0
I want to find the potential of a conducting disk in space whithout laplace equation.(i know how to do that).I want to use the potential of a uniformly charged rod.because its equipotentials are ellipsoids(ellipses rotated around the rod).now a disk is a limiting case of an ellipsoid.
I can't get through the math part.can someone write and simplyfy it?
because a disk is an ellipsoid where semi major axis approaches zero and semi minor axis approaches R then c approes iR !
 
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  • #2
This site is turning me down.c'mon guys!its not a hard problem!I mean I may not be able to do it but guys who go to the university must be able to!
 
  • #3
It's easiest to just solve the poissons equation.
Not sure what alternate method you are suggesting here.
I thought you could only get the field on the symmetry axis without poissons?
 
  • #4
Let me clear it up.by integration we can simply get the potential of a rod with uniform charge density in space.putting its potential CONST and then doing some algebra we find out its equipotentials are ellipses whose centers are at the edge of the rod(in 2D.in 3D its just ellipses rotated about the rod,i think they call'em ellipsoids).
so if we have a conducting ellipsoid,it means that we we have an ellipsoid at a CONSTANT potential>>so we simply forget about the ellipsoid and put a rod instead.in analogy with what we prooved we can simply find out a rod of what length and charge per length will do the job.
so we have the potential of an ellipsoid in space!(we use the potential of rod except that we right its landa and lenght(L) in terms of V of the conductor and its sami major axis).
now a disk is an ellipsoid really.(in the limit that its z length is zero.)
now we just have to take a limit of what we find for a rod to get the potential of disk in space.but it gets TRICKY!mathematically!
 
  • #5
Sounds like a steange way to go at it, why not just brute force integrate it with the free space green function?
 
  • #6
its simple!the final answer is going to come up simple.and the brute force way is HARD!
but we have the potential.we just need to plug in the according prameters!which is much simpler then doing the BRUTE FORCE integral which can't be done!
 

1. What is the purpose of finding the potential of a conducting disk?

The potential of a conducting disk is important in understanding the behavior and properties of electric fields. It helps in determining the flow of electric current and the distribution of charges on the surface of the disk.

2. What is the formula for finding the potential of a conducting disk?

The formula for finding the potential of a conducting disk is V = (Q/2πε₀)(1/r), where V is the potential, Q is the charge on the disk, ε₀ is the permittivity of free space, and r is the distance from the center of the disk.

3. How is the potential of a conducting disk related to its electric field?

The potential of a conducting disk is directly related to its electric field. The electric field at any point on the surface of the disk is equal to the negative gradient of the potential at that point.

4. Can the potential of a conducting disk be negative?

Yes, the potential of a conducting disk can be negative. This indicates that the electric field is directed towards the center of the disk, which is the region of lower potential.

5. What factors can affect the potential of a conducting disk?

The potential of a conducting disk can be affected by the charge on the disk, the distance from the center of the disk, and the permittivity of free space. It can also be influenced by the presence of other nearby charged objects and external electric fields.

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