Natural potassiu, has an atomic weight of 39.089 and contains 0.0118 atomic percent of the isotope 19 K 40, which has 2 decay modes:(adsbygoogle = window.adsbygoogle || []).push({});

19 K 40 -> 20 Ca 40 + beta particle + neutrino (nu bar)

19 K 40 + e- -> 18 Ar 40 * + beta particle + neutrino (nu no bar)

where 18 Ar 40 * means an excited state of 18 Ar 40. In this case, this excited state decays to the fround state by emitting a single gamma ray. The total intensity of beta particles emitted is 2.7*10^4 kg^-1 . s^-1 of natural potassium and on average there are 12 gamma rays emitted to every 100 beta particles emitted. Estimate the mean life of 19 K 40.

If someone can set up the question for me, I will take it from there. I am very confused right now as to how the intensity can be used to compute the lifetime. Can someone please explain this using equations?

James

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# Homework Help: Tricky mean life question (potassium)

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