Radioactivity

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How are the terms "activity" and "becquerel" related?

A radioactive isotope source has a mass of 120 g. If the isotope has a half life of 20 secs what would be the mass of the isotope in 2 mins?

  • Radioactivity -

    k = 0.693/t1/2
    Substitute k into the equation below.
    ln(No/N) = kt
    No = 120
    N = ?
    k from above
    t = 120 seconds (since the half life is given in sec you will have a seconds terms for k so you must convert 2 minutes to seconds).
    Solve for N.

    See the link below for the definition of Bq.
    http://en.wikipedia.org/wiki/Becquerel

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