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Homework Help: Find the percentage of electrons were removed?

  1. Aug 22, 2011 #1
    1. The problem statement, all variables and given/known data
    A neutral object contains an equal number of positive and negative charges. A particular neutral object contains 7.2e26 electrons. If 9.5e6 electrons are removed, what percentage of the electrons where removed?

    2. Relevant equations
    coulomb = 6.24e18 electrons

    elentary charge = 1.6 E -19 coulombs

    3. The attempt at a solution
    I'm having difficulties of solving the percentage of the electrons were removed,

    I did this:

    9.5e6 / 7.2e26 = 1.32e-20

    But the answer says it's 1.32e-18, so I don't know how it got that answer.

    Any help will be appreciated.

  2. jcsd
  3. Aug 22, 2011 #2


    Staff: Mentor

    To convert a number to a percentage, multiply by 100.
  4. Aug 22, 2011 #3
    Wow, I forgot about that. What am I thinking? haha thanks.
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