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Homework Help: Radioactive reactions -half-life Decay physics 30

  1. Jan 1, 2008 #1
    1. hi i would like to now how i could do this?
    the question says:
    iodine-131 is a radiactive element used in the medical diagnosis and treatment of thyroid problems. iodine-131 undergoes simultaneous beta and gamma decay and has a half-life of 8.00 days.

    2.im ask to write the complete decay equation for iodine-131

    3. i know the formula for the life time is N=No(1/2)^n and n=time after/half-life...T(1/2)
    but im not sure if thats the equation to do the decay...
    ...or the complete decay equation they are asking for is a series of radioactive elements.. like the folowing
    ex: 226 Ra--->222 Rn + 4 He
    ....... 88.............86..........2

    if is as the example im not sure how to do it..could someone explain me how could i do it ? thanks
    Last edited: Jan 1, 2008
  2. jcsd
  3. Jan 3, 2008 #2

    Shooting Star

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    Yes, this is what they are asking.

    If an electron is emitted by the nucleus, what happens to the atomic number?
  4. Jan 3, 2008 #3
    Since they mention it's a beta emitter, but also mention the half life, I can see the confusion. Typically, in health physics and nuclear engineering, when asked for the decay equation for a radioactive element, it's asking for A(t) = A(0)exp(-lambda*t). However, it (i.e., the decay equation) is sometimes used in the second manner, as pointed out by Shooting star. I suppose it depends on the chapter of the book you're using. From the title of your post, it says half life decay, so I would go with the first
  5. Jan 3, 2008 #4

    Shooting Star

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    After reading the original post once more, I agree with user daveb. Sorry for misleading the OP a bit.
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