# What is the potential energy of this group of charges?

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1. Feb 15, 2016

### neilson18

1. The problem statement, all variables and given/known data
Three electrons form an equilateral triangle 0.800 nm on each side. A proton is at the center of the triangle.

2. Relevant equations
U = k[(q_1*q_2)/r]

3. The attempt at a solution
I tried to use the following equation:

k*[(3e^2)/(0.8*10^-9) - (3e^2)/(0.4*10^-9)]

I plugged in 1.602*10^-19 for both e-values, and got the following answer:

-6.4*10^-19 Volts

However, it says that "I do not have the correct dimensions." I'm not sure what that error means or what I did wrong, so any help would be appreciated.

2. Feb 15, 2016

### Staff: Mentor

There's no question in your problem statement... thread titles don't really count as part of the problem statement.

"Dimensions" refer to the units associated with your answer. What are the units of potential energy, as opposed to electric potential?

3. Feb 15, 2016

### neilson18

Oh my goodness what a dumb mistake! thank you!