A 2.71g sample of KCL is found to be radioactive, and it is decaying at a constant rate of 4490 Bq. The decays are traced to the ekement potassium and in particular to the isotope K(proton number 40), which constitutes 1.17% of normal potassium. find the half-life of this nuclide( Take molar mass of KCL = 74.555g)(adsbygoogle = window.adsbygoogle || []).push({});

Ans provided is 1.25 x 10^9 years. I cant seem to even come close to that value.

I found the number of K-40 in the sample which is 2.560 x 10^20. From there, using A= constant x number of particles of K-40 and rate of decay = -dN/dt, I cant seem to get that ans

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# Homework Help: Radioactive Decay question

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