# Uniform electric field interaction

1. Homework Statement
Electric charge is distributed along each side of a square. Two adjacent sides have positive charge +Q on each, two sides have -Q on each.

What are the x and y components of the net electric field at the center of the square? (Each side has length "a").

2. Homework Equations
E=F/q ?
F=k*q1*q2/r^2
k=9E9Nm^2/C^2

3. The Attempt at a Solution
Trying to come up with a differential equation? I don't know how to begin with having 4 sides.

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marcusl
Gold Member
You need the formula for the electric field from a charge (look in your book). Then argue from the special symmetry at the center of the square.

You need the formula for the electric field from a charge (look in your book). Then argue from the special symmetry at the center of the square.
You mean the diagonal symmetry?

edit: Then that would make it equal 0 at the center?
I was thinking it was zero?

Last edited:
marcusl