Finding the electric field of following setup

[brainslush]

Homework Statement

Assume two perpendicular planes one with charge density $\sigma$ and the other with a charge density $2\sigma$. Find the electric field.

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$\sigma$ |
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//|////// $2\sigma$///////////////
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Homework Equations

The Attempt at a Solution

I got a question. Can I assume that the planes are infinitly long, specially close to the origin? In such a case, I could apply the Gaus-law.

 

[gneill]

Hi brainslush. By definition a plane is of infinite extent. If you know the result for the field due to an infinite plane of a given charge density, then you're (almost literally) halfway there!