Basic Gaussian Surface Conceptual Problem

In summary, the conversation discusses a solid copper cube with a hollow sphere at the center containing a charge Q. The question is about the total charge induced on the surface of the void. The solution involves setting up a gaussian surface and understanding the properties of copper as a conductor. It is determined that the total charge on the surface of the void is -Q.
  • #1
fysicsandphol
6
0
So I'm pretty sure I have the right answer I just want to make sure I am getting the idea.

There is a large solid copper cube. At the center of the cube there is a hollow sphere of radius a. At the center of the hollow sphere there is a charge Q.
What is the total charge induced on the surface of the void?

To solve it, I set up a gaussian surface enclosing the hollow sphere. Because copper is a conductor, (ignoring other forces), the E field must be zero everywhere within the solid copper, otherwise ions would move to balance the E field (right?). Therefore the closed integral of E dot dA will always be zero. This implies the charge encapsulated must be 0. This implies that there must be a total charge of -Q on the surface of the void. Is this right?
 
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  • #2
Yes, that's correct.
 
  • #3
thanks
 

FAQ: Basic Gaussian Surface Conceptual Problem

1. What is a basic Gaussian surface?

A basic Gaussian surface is a hypothetical surface used in Gauss' law, a fundamental law in electrostatics. It is an imaginary closed surface that allows us to calculate the net electric flux through the surface from a given charge distribution.

2. How is a Gaussian surface different from a regular surface?

A Gaussian surface is different from a regular surface in that it is imaginary and does not exist physically. It is used as a mathematical tool to simplify calculations in electrostatics.

3. What is the purpose of using a Gaussian surface in electrostatics?

The purpose of using a Gaussian surface in electrostatics is to apply Gauss' law, which states that the electric flux through a closed surface is proportional to the net charge enclosed by the surface. This allows for easier calculation of electric fields in situations with high symmetry.

4. How do you choose the shape and size of a Gaussian surface?

The shape and size of a Gaussian surface are chosen based on the symmetry and distribution of charges in a given problem. The surface should enclose the charges of interest and have a shape that simplifies the calculation of electric flux.

5. Can a Gaussian surface be used in situations with non-uniform charge distributions?

Yes, a Gaussian surface can be used in situations with non-uniform charge distributions. In these cases, the surface is divided into smaller parts, and the electric flux through each part is calculated separately. The total electric flux is then found by summing the flux through each part.

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