Tritium is a radioactive nucleide with a half life of 4500 days, determine the time for 90% of it to decay.
We know that the number of undecayed nuclei, N, is given by N=N0e-lambda t. From this, by setting N=N0/2 we know at this point that t= T0.5 (the half life) and can show that lambda =ln(2)/T0.5 . Hence we can calculate lambda as 1.54 x10-4 days-1. Now using the original form by setting N=0.1N0 we can get t = -ln(0.1)/lambda=14952 days.
LC
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