What is the electric potential at points A and B?

[Cauchemar]

Homework Statement

They're in the attachment

Homework Equations

V=kQ/r

The Attempt at a Solution

I was absent during this class,so I have no idea,but I attempted question a which is the potential at point a,b
Point a=(9*10^9 * 10*10^-6/0.2)
Point B=(9*10^9 * -8*10^-6/0.3)

 

[tnich]

Homework Statement

They're in the attachment

Homework Equations

V=kQ/r

The Attempt at a Solution

I was absent during this class,so I have no idea,but I attempted question a which is the potential at point a,b
Point a=(9*10^9 * 10*10^-6/0.2)
Point B=(9*10^9 * -8*10^-6/0.3)

Don't you think the potential at a given point would be a function of all of the charges?

 

[kaashmonee]

The potential is a scalar quantity. Simply find the potential due to A, the potential due to B, and add them up. Here is an algebraic solution:

We know that $V = \frac{kQ}{r}$. So, $V_A$ will be given by $$V_A = \frac{kQ_1}{r_1} + \frac{kQ_2}{r_2}$$, where $r_1$ and $r_2$ are the distances between the point charges. Do the same for part B.