1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: What is the potential energy of this group of electron charges?

  1. Feb 25, 2008 #1
    1. The problem statement, all variables and given/known data
    Three electrons form an equilateral triangle 1.10 nm on each side. A proton is at the center of the triangle.
    What is the potential energy of this group of charges?

    2. Relevant equations

    potential energy = U = kq1q2/r

    3. The attempt at a solution

    So, I was assuming that the three electrons, since they form an equilateral triangle, their charges will cancel out and I should just find the potential energy based on the positive charge.

    so then I substituted q1 for the proton, but then since there is a q2, i also tried to use the charge of an electron.

    also, I found the radius from the center proton of the triangle to the corner electron of the triangle to be 0.635 m

    I'm just not sure what to do anymore I only have a few attempts left
  2. jcsd
  3. Feb 25, 2008 #2
    ?? meter ??
    I will take it as 0.635 nm.:rolleyes:

    potential energy of the system=[tex]k[\frac{3e^2}{1.10X10^-9}-\frac{3e^2}{0.635X10^-9}][/tex]

    We can make three electron-electron pairs and three proton-electron pairs.
    Last edited: Feb 25, 2008
  4. Sep 20, 2011 #3

    So what am I supposed to plug in for e? +1, -1 ???????
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook