What is the Relationship Between Net Flux and Total Charge for a Cube?

[baird.lindsay]

Homework Statement

When is the net flux for a cube 0 and when is it not?

Homework Equations

∫EdA= Q/8.85E-12

The Attempt at a Solution

if you have no test charge then the flux of a cube is zero. but if you have a test charge then the net flux is the charge divided by 8.85E-12. I just want to make sure I am thinking about this correctly.

 

[SammyS]

Homework Statement

When is the net flux for a cube 0 and when is it not?

Homework Equations

∫EdA= Q/8.85E-12

The Attempt at a Solution

if you have no test charge then the flux of a cube is zero. but if you have a test charge then the net flux is the charge divided by 8.85E-12. I just want to make sure I am thinking about this correctly.

It has nothing to do with a test charge.

What does the Q represent in Gauss's Law? $\displaystyle\ \int \vec{E}\cdot\vec{dA}=\frac{Q}{\varepsilon_0} \ ?$

 

[baird.lindsay]

Q is the total charge...

 

[SammyS]

Q is the total charge...

The total charge of what? ... Where is this charge located?

 

[dirac1933]

So far you are on the right track... Just think about where the charge is in relation to your Gaussian Surface. It's very important that you understand this!

 

[dirac1933]

Look closely at the form of the Equation:


\oint\vec{E}\cdot\vec{dA}


What are the implications of the closed integral?

 

[baird.lindsay]

The total charge of what? ... Where is this charge located?

Q is the total charge enclosed by the surface. its located in the center of the surface...Im not sure I understand.