A certain amount [itex]N_0[/itex] of a radioactive isotope with decay constant [itex]\lambda_1[/itex] is injected into a pacient. Besides that isotope's natural decay process, there's also a biological elimination process, with decay constant [itex]\lambda_2[/itex].(adsbygoogle = window.adsbygoogle || []).push({});

Now, at time t, the number of remaining isotope atoms is given by [itex]N(t) = N_0 e^{-(\lambda_1 + \lambda_2) t} [/itex]. My question is, how do I calculate the number of atoms that, at time t, have decayed by *one* specific process (e.g. by radioactive decay alone)? I don't think I can use the above equation, with [itex]\lambda_1[/itex] instead of the sum, because such an equation would describe the number atomsassuming that that only one decay process is occuring(the one characterized by the used value of [itex]\lambda[/itex].

How to proceed then?

Thanks in advance for your help.

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# Homework Help: Number of decayed atoms in a simultaneous decay process

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