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Homework Help: Electrical charge problem (need assurance on an answer)

  1. Feb 27, 2013 #1
    1. The problem statement, all variables and given/known data

    Dry air will break down and generate a spark if the electric field exceeds about 3.0\times 10^6 N/C How much charge could be packed onto a green pea (diameter 0.81cm ) before the pea spontaneously discharges?

    2. Relevant equations

    E = kQ/r^2
    Q = Er^2/ k <-------this is the equation to use I believe
    3. The attempt at a solution

    resulting in an answer of 4.845160214*10-9 = 5*10-9

    does this look right to you guys?
  2. jcsd
  3. Feb 27, 2013 #2


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    Homework Helper

    The radius is not 3.81*10-3 m. Check.

  4. Feb 27, 2013 #3
    figured it out, the diameter is .405
    so the answer would be
    (3*106)(4.05*10-3)2/8.988*109 = 5.5 *10^-9
    Thank you for your help
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