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Flux through each face on a cube

  • Thread starter Ed Aboud
  • Start date
197
0
1. Homework Statement

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. Homework 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.
 
139
12
By Gauss's Law, the flux through the whole cube is just [tex] 6q/\epsilon_0 [/tex]. Now, apply a simple symmetry argument to get the answer.
 
197
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I'm not sure why is it 6q ? If there is only one charge of magnitude 1q surely the flux is

[tex]
q/\epsilon_0
[/tex]
 

Doc Al

Mentor
44,803
1,061
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.)
 
197
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Ah right I see now. Thanks very much, was thinking about this completely the wrong way.
 
318
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Ah right I see now. Thanks very much, was thinking about this completely the wrong way.
So...
What is the answer you are getting?
 

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