Calculate Sum of Charges at Point A/B

[somasimple]

Homework Statement

Attached figure.
3 charges : q1, q2 and q3 are on a plane (for simplification).
We want to compute the resulting charge at some point of the plane.
1/ Is it possible to sum (for computation) these charges to an arbitrary point A?
2/ or B?

Homework Equations

these ones ?
http://www.ux1.eiu.edu/~cfadd/1160/Ch17/Vector.html
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/mulpoi.html

The Attempt at a Solution

I supposse I can't do it directly. I may use force or voltage or electric field?

 

[Office_Shredder]

I'm not sure what you're looking for. The charge at point A is zero, because there is no charge there.

 

[somasimple]

I want to combine the 3 charges at point A or B.
I know that is possible to compute the voltage V=kq1/r1...
I'm interested in the result charge (virtual).

 

[Pengwuino]

You can determine the potential or electric field at the point A, but you can't just reform the problem and just place a charge at an arbitrary point.

 

[somasimple]

OK thanks but is it possible to compute the potential or EF at B (since distance becomes null)?

 

[Vyse007]

Well, if B is a point inside the sphere, and if the said sphere is hollow, then you can find the electric field I think...of course, the field will be zero inside the shell if its conducting.

 

[somasimple]

Thanks.