# Homework Help: Flux of a cube

1. Feb 10, 2007

### stylez03

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
4*pi*Q

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. Feb 10, 2007

### 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.

3. Feb 10, 2007

### stylez03

Is the flux on any surface that surrounds a charge Q => Qenclosed / Eo

Last edited: Feb 10, 2007
4. Feb 10, 2007

### Staff: Mentor

Yes it is.

5. Feb 10, 2007

### stylez03

Though with this, knowledge, I'm still not sure how to figure out the flux on each side of the cube.

6. Feb 10, 2007

### Staff: Mentor

Start by figuring out which side has the most flux passing through it.

7. Apr 17, 2007

### muchoboosto

hummm is it Q/Eo/6?