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Half Life

  1. Sep 21, 2003 #1
    [SOLVED] Half Life

    I can't get the answer to this question.
    If Hydrogen 3 ( 3H )
    ( 1 )
    has a half life of 12.5a, how many years have passed when only 1/64 of its original mass remains?
  2. jcsd
  3. Sep 21, 2003 #2


    User Avatar

    Staff: Mentor


    Half life is a pretty simple thing, you can count this one on your fingers. 1 half life is 1/2, 2 half lives is 1/4, 3 is 1/8, 4 is 1/16, 5 is 1/32, and 6 is 1/64.

    But I don't know what "12.5a" means.
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