Uniform electric field interaction

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Homework Help Overview

The problem involves calculating the net electric field at the center of a square with electric charges distributed along its sides. Two adjacent sides have positive charge +Q, while the other two sides have negative charge -Q. Each side of the square has a length "a".

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to formulate a differential equation but expresses uncertainty about how to approach the problem with four sides. Some participants suggest using the formula for the electric field from a charge and considering the symmetry at the center of the square. There is a discussion about whether the net electric field could be zero at the center, with some questioning the implications of diagonal symmetry.

Discussion Status

Participants are exploring different interpretations of the problem, particularly regarding the symmetry and contributions of the electric field from each side. Some guidance has been offered about integrating the electric field contributions and considering the symmetry, but there is no explicit consensus on the net electric field's value at the center.

Contextual Notes

There is an indication that participants are working under the constraints of homework rules, which may limit the extent of guidance provided. The original poster's uncertainty about the setup and approach is evident.

kvanr
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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").

Homework Equations


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

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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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.
 
marcusl said:
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:
Well, pick a side (say the top) and integrate the field at the center as you move the source point along (left to right). Mentally summing the vectors (look at the symmetry) will show you the net direction even without doing the math. Now that you know the answer for one side, it's straightforward to add the contributions of other three.

Hint: the field is not 0 at the center.
 

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