Flux of a cube

  1. Electric Flux of a cube

    1. The problem statement, all variables and given/known data
    A point charge of magnitude 9.10 nC is at the center of a cube with sides of length 0.685 m.

    What is the electric flux through each of the six faces of the cube?

    What would be the flux Phi_1 through a face of the cube if its sides were of length 0.250 m?

    2. Relevant equations

    3. The attempt at a solution

    I tried 4*pi*9.10 which equals 411 and it says I'm off by an additive constant

    I know to do part2, the flux must be found for part1 but i'm not sure if i'm applying gauss's law correctly, I know that you can use symmetry to solve these cube problems but I haven't had a decent example of this type of problem and we already have hw on it.
    Last edited: Feb 10, 2007
  2. jcsd
  3. Doc Al

    Staff: Mentor

    Hint: What's the total flux through any closed surface that surrounds a charge Q? Once you find the total flux, then use symmetry to find the flux through each side of the cube.
  4. Is the flux on any surface that surrounds a charge Q => Qenclosed / Eo
    Last edited: Feb 10, 2007
  5. Doc Al

    Staff: Mentor

    Yes it is.
  6. Though with this, knowledge, I'm still not sure how to figure out the flux on each side of the cube.
  7. Doc Al

    Staff: Mentor

    Start by figuring out which side has the most flux passing through it. :wink:
  8. hummm is it Q/Eo/6?
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