What is the Electric Field at Point P in the Presence of Two Charges?

AI Thread Summary
To determine the electric field at point P due to two charges, the relevant equation is F = k*(q1*q2)/r^2. The electric fields from each charge act in opposite directions, so the net electric field at point P is found by calculating the individual fields and taking their difference. The correct expression for the electric field at point P is kq/2d^2. This approach clarifies the interaction between the two charges and their effect on the electric field at the specified point.
JJones_86
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Homework Statement


In the figure below , what is the electric field at point P?
2qx594z.gif


Homework Equations



F = k*(q1*q2)/r^2


The Attempt at a Solution



F = k*(2q^2) / (2d + d)^2


That is my attempt, but it's not a possible answer.. Any help is appreciated.
 
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At P the fields are in the opposite direction. So find the field at P due to q and 2q, and take the difference.
 
rl.bhat said:
At P the fields are in the opposite direction. So find the field at P due to q and 2q, and take the difference.

Oh ok, so it should be kq/2d^2 then?
 
Yes.
 

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