Electric Potential due to multiple charges

[irivce]

Homework Statement

Homework Equations

E = kq₁q₂/r²

The Attempt at a Solution

Please correct me if I am wrong but I think it is A. Since doubling the charge, doubles the potential as well, while doubling the radius between the charges would just exponentially decrease the electric potential. My question here is if that is the correct equation?

 

[Tsunoyukami]

Be careful. This questions asks you which statement is true about the electric potential - not the electric field. Recall that the electric potential produced by a point charge Q is given by the expression:

$V = k \frac{Q}{r}$

where Q is the charge and r is the distance away from this charge. (This is the source charge).

 

[irivce]

So is it safe to say that the charge from the second point is irrelevant ?

 

[Tsunoyukami]

That is correct. The electric potential at a point in space is independent of the test charge.

Some light reading from wikipedia for you (I especially recommend the introduction and the section titled electric potential due to a point charge): http://en.wikipedia.org/wiki/Electric_potential