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Homework Help: One last Radioactivity Question

  1. Dec 30, 2008 #1
    One last Radioactivity Question!!

    Im not sure how to do this calculation

    Cells containing 0.8 curies of 32P were to be disposed of as waste when their total radioactivity had decreased to less that uCi. Calculate the period for which these should be stored

    Now 32P has a half life of 14.2 days?

    Im sorry to bother you guys but I have a test on monday and this could be a question. Thanks in advance!

    How does this answer look??

    A = B*(1/2)^(t/14.2)

    at t = 0, B = 0.8 curie,

    A = 0.8*(1/2)^(t/14.2)

    when A = 1 uCi

    0.000001 = 0.8*(1/2)^(t/14.2)

    0.000001/0.8 = (1/2)^(t/14.2)

    t/14.2*log(1/2) = log(0.000001/0.8)

    t = 14.2*log(0.000001/0.8)/log(1/2)

    t = 278.46 days
  2. jcsd
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