kolahalb

electrostatics

2 posts in this topic

Well,I think this is interesting.I invite people to think over it.

consider a charged spherical shell.Throughout its interior,E=0.

Now,consider the centre.From Laplace's equation and Earnshaw's theorem,this point is not a point of potential minimum.So,a charge at this point cannot be in stable equilibrium.Say,you displace it slightly.

What do you find.It just gets stagnant where you left it!

If this is not a point of stable eqlbm,it is not also a point of unstable equilibrium.

So,is it a point of neutral equilibrium?

Apparently seems so.But,I wish to confirm.

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If this is not a point of stable eqlbm,it is not also a point of unstable equilibrium.

So,is it a point of neutral equilibrium?

Yes. For Earnshaw's theorem there is no stable equilibrium throughout the entire vacuum, not just the center. Also note that for a dielectric with relative permittivity greater than 1, the center equilibrium is unstable. However, for a paraelectric medium it has been shown that the center of the sphere is a point of stable equilibrium. Life can become complicating. :)

I see you are new to THE FORUM. These can be interesting questions, but here we usually discuss physics in some relation to the prime purpose of our forum, as fans of Ayn Rand. There are other physics-related forums, including homework help forums, that are more suited to these sort of questions.

Also, please read over our Guidelines for posting. We do require properly formatted and properly spaced sentences. Thanks.

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