Flux through each face on a cube

[Ed Aboud]

1. The problem statement, all variables and given/known data

A point charge q is placed at one corner of a cube of edge a. What is the flux through each of the cube faces?


2. Relevant equations



3. The attempt at a solution

I drew a diagram of the situation. I'm pretty sure that I should use Gauss' Law and some symmetry arguments but I am not sure how to integrate over the cubes faces taking into account that the electric field produced by the point charge is radially outwards, like a sphere cutting through the face of the cube ( poorly described I know, sorry).

Thanks for the help.

[VKint]

By Gauss's Law, the flux through the whole cube is just 6q/\epsilon_0 . Now, apply a simple symmetry argument to get the answer.

[Ed Aboud]

I'm not sure why is it 6q ? If there is only one charge of magnitude 1q surely the flux is


q/\epsilon_0

[Doc Al]

Right: The total flux from that charge is just q/ε0. So what's the total flux through the cube? Through each face of the cube? (No integration needed, just symmetry.)

[Ed Aboud]

Ah right I see now. Thanks very much, was thinking about this completely the wrong way.

[FedEx]

Ah right I see now. Thanks very much, was thinking about this completely the wrong way.

So...
What is the answer you are getting?