# Activities of Radionuclides

A radioactive sample consists of a mixture of S-35 and P-32. Initially, 5% of the activity is due to the S-35 and 95% due to the P-32. At what subsequent time will the activities of the two radionuclides in the sample be equal?

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The rate for radioactive decay is given by:

n = dN/dt = -alpha(N)(t)

Where alpha is proportionality constant, to be determined from half-life data.

The solution to this differential equation is:

N(t) = (N_0)(e^-(alpha(t)))

Where N_0 is the initial number of radioactive nuclei. ...

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