How does symmetry affect the shell theorem?

In summary, Gauss' shell theorem states that for a spherical shell with uniformly distributed charge on its surface, the net electric field inside the sphere is zero. However, if the charge is not uniformly distributed, the field inside will not be zero everywhere. This can be proven using superposition, where a non-uniform charge distribution will result in a non-zero field at certain points inside the sphere. Therefore, the hypothesis that the field is zero everywhere cannot hold true if there is a non-uniform charge distribution.
  • #1
Bipolarity
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Gauss' shell theorem states that if given a spherical shell of charge such that the charge is uniformly distributed on the surface, the net electric field anywhere inside the sphere is zero.

But I'm wondering (and turns out this was on a past exam), what happens if the charge is not uniformly distributed?

Will the field anywhere and everywhere inside the shell STILL be 0?

My hypothesis is that it cannot be 0 everywhere, since even though Gauss' law can be used to prove that the flux is zero, spherical symmetry cannot be used to take the E vector out of the loop integral since there is no uniform charge distribution.

My other explanation was that 0 field everywhere inside would necessarily imply a uniform charge distribution which is against the framework of the question...

Thoughts?
 
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  • #2
It's non-zero. You can prove it by superposition: Suppose the charge is distributed uniformly everywhere except at a point. Then the field is the sum of a uniform field (i.e., zero inside the sphere) and the excess field at the point (non-zero everywhere).
 

FAQ: How does symmetry affect the shell theorem?

1. How does symmetry affect the shell theorem?

The shell theorem states that the gravitational force exerted by a spherically symmetric body on a particle outside of the body is the same as the force that would be exerted if all the body's mass were concentrated at its center. This means that the distribution of mass within a spherically symmetric body does not affect the gravitational force on particles outside of it.

2. Does symmetry affect the strength of the gravitational force?

No, symmetry does not affect the strength of the gravitational force. As stated in the shell theorem, the gravitational force on a particle outside of a spherically symmetric body is solely dependent on the total mass of the body and the distance between the particle and the center of the body.

3. How does non-spherical symmetry impact the shell theorem?

If a body does not have spherically symmetric mass distribution, the shell theorem does not apply. In this case, the gravitational force on a particle outside of the body will be affected by the distribution of mass within the body and may vary depending on the particle's location relative to the body.

4. Can the shell theorem be applied to bodies of any size?

Yes, the shell theorem can be applied to bodies of any size, as long as they have a spherically symmetric mass distribution. This means that the theorem is applicable to objects ranging from small planets to massive stars and galaxies.

5. How is symmetry related to the center of mass in the shell theorem?

In the shell theorem, the center of mass of a spherically symmetric body is considered to be at its center. This is because the theorem states that the gravitational force on a particle outside of the body is the same as if all the body's mass was concentrated at its center. Therefore, symmetry is closely related to the concept of center of mass in the context of the shell theorem.

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