Gaussian Surfaces and infinite lines of charge

In summary, the conversation discusses the electric field of a plane of infinite charge and a line of infinite charge. It is concluded that the electric field for a plane does not depend on distance, while the electric field for a line does depend on the radius of the cylinder used as a Gaussian surface. This may seem contradictory to the initial conclusion, and further information can be found on the provided link.
  • #1
JustStudying
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So I've been wondering..
from my previous post: https://www.physicsforums.com/showthread.php?p=4500082#post4500082

if we have a plane of infinite charge, then electric field does not depend on distance

however, for a infinite line of charge:
If we use a cylinder with radius 'r' as our gaussian surface then
the electric field has the equation

E = (charge density)/ (2∏ε * r)

which now depends on the radius of the cylinder.

This suggests that the electric field actually will have different values for different radius values
which (i feel) don't line up with the conclusion I reached in my first thread 'if we have a plane of infinite charge, then electric field does not depend on distance'

Any help?
 
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1. What is a Gaussian surface?

A Gaussian surface is an imaginary surface that is used in the process of calculating electric flux in a region. It is often used in conjunction with Gauss's Law, which states that the electric flux through a closed surface is equal to the enclosed charge divided by the permittivity of the medium.

2. How does a Gaussian surface help in calculating electric flux?

A Gaussian surface simplifies the calculation of electric flux by providing a symmetrical surface where the electric field is constant. This allows for the use of Gauss's Law, which makes the calculation easier by reducing the number of variables.

3. Can a Gaussian surface be of any shape?

No, a Gaussian surface must be a closed surface. This means that it must completely enclose the charge or charges being considered. The shape of the surface can vary, but it must be closed and symmetrical to use Gauss's Law.

4. What is the relationship between a Gaussian surface and an infinite line of charge?

A Gaussian surface can be used to calculate the electric field of an infinite line of charge. The Gaussian surface would be a cylindrical surface with the line of charge passing through its center. This allows for a simplification of the calculation, making use of the symmetry of the problem.

5. Can a Gaussian surface be used to calculate the electric field of non-uniform charge distributions?

Yes, a Gaussian surface can be used to calculate the electric field of non-uniform charge distributions. This can be done by dividing the non-uniform charge distribution into smaller, symmetrical sections and using the principle of superposition to calculate the total electric field.

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