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fobos3
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I heard it's quite hard to prove that electric charge is distributed uniformly on a disk conductor. Can you point me to some resources online on the subject?
zhermes said:Consider any non-uniform distribution of charge. In this case there will be some charges closer to each-other than others. Therefore there will be a greater repulsive force between the nearer charges, tending to move them away. The only equilibrium position, is uniformly distributed. (With friction dissipating energy to prevent oscillation)
You could 'prove' this more rigorously by making an equation for the total potential energy of a configuration of charges (e.g. in a grid with variable x and y spacing). Its easy to show that the lowest energy (most stable) configuration is that with uniform separation.
Eynstone said:The statement should read 'At equilibrium,electric charge is distributed uniformly on a disk conductor'. Nothing keeps the charges from moving when in a non-equilibrium configuration.
A rigourous proof can be given with calculus of variations.Assume a charge density function which minimises energy & equate it's variation to zero . Using Gauss's law,you get that the function must be a constant.
fobos3 said:I understand and can prove the electrostatics case. What I don't understand is that if you have a non-uniform distribution of charge, it rearranges itself to an equilibrium position. Why is that?
AJ Bentley said:This applies whatever the shape of the conductor.
Ben Niehoff said:Not so! The surface of the conductor must be flat.
That's true but I'm having a hard time trying to determine if the charge distribution can be anything other than uniform.Ben Niehoff said:On a sphere, the mean curvature is constant, and so the distribution is uniform. ;)
fobos3 said:I heard it's quite hard to prove that electric charge is distributed uniformly on a disk conductor. Can you point me to some resources online on the subject?
The charge on a disk conductor is distributed uniformly, meaning that each point on the disk has the same amount of charge per unit area.
Uniform charge distribution on a disk conductor helps to ensure that the electric field is also uniform, making it easier to calculate and predict the behavior of the system.
One way to prove uniform charge distribution on a disk conductor is by using Gauss's Law, which states that the electric flux through a closed surface is equal to the total charge enclosed by that surface divided by the permittivity of free space.
Yes, the uniform charge distribution on a disk conductor can be affected by factors such as the presence of nearby conductors, the dielectric constant of the surrounding medium, and the potential difference applied to the conductor.
Yes, there are many real-life applications of this concept, such as in capacitors, where uniform charge distribution on the conductive plates is necessary for their proper functioning. It is also important in the design of electronic devices and equipment.