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Homework Help: Half-Life ( not the game, sorry )

  1. Jan 22, 2009 #1
    1. The problem statement, all variables and given/known data
    k so An experiment is done to determine the half-life of a radioactive substance that emits one beta particle for each decay process. Measurements show that an average of 8.4 beta particles are emitted each second by 2.5 milligrams of the substance. The atomic weight of the substance is 230. find the half-life of the substance...

    2. Relevant equations
    New Mass=Origonal mass(1/2) time/halflife

    3. The attempt at a solution

    i cant sort out where the 2.5 milligrams go, and how to measure the atomic weight properly, meaning, where i place it in the equation
  2. jcsd
  3. Jan 23, 2009 #2


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    Homework Helper

    Number of radioactive atoms in 230 g is equal to the Avogadro's number. Find the number of atoms in 2.5 milligrams. Activity is given. It is proportional to the number of atoms. From this find lmbda. Using the relation between lambda and half life find the half life.
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