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Homework Help: Figuring out the magnitude of electric repulsion

  1. Jul 11, 2015 #1
    1. The problem statement, all variables and given/known data

    In a certain organic molecule, the nuclei of 2 carbon atoms are separated by a distance of .20nm, What is the magnitude of the electric repulsion between them?

    Now, I know the distance between them, but it has to be converted into meters:

    .20nm = .20 X 10 ^-9m

    And k is a proportionality constant, equaling:

    8.99 X 10 ^9.

    2. Relevant equations

    So I am using Coulomb's law for this which states

    F = (K|q1| |q2|)/r^2

    3. The attempt at a solution

    The only unknowns are q1 and q2. In order to solve for those, I have to know the magnitude of their charge. Since there are 6 protons in a Carbon atom, in order to get the charge I multiply 6 by e, which equals:

    1.60X10^-19 C

    I have solved for all the unknowns, so all that is left is to plug in all the variables and solve for the F.

    F = (8.99 X 10 ^9 * (6*1.60X10^-19)^2)/(.20 X 10 ^-9m)^2

    This gives me the final answer of:

    2.07x10^-7 N

    I wanted to verify that my math and reasoning behind my calculations were correct. Thanks!
  2. jcsd
  3. Jul 11, 2015 #2
    Reasoning looks pretty good to me.
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