Question

Chromium-51 is a radioactive isotope used to label red blood cells to identify if they remain intact in the body. It has a half-life of 27.7 days. If 0.25 mg is an approximate dose amount, how much remains after 83.1 days?

Answer 1

$N(t)=N_{(0)}*(\frac{1}{2})^{\frac{t}{\tau_{\frac{1}{2}}}}\\\\ N_{0}=0,25mg\\ t=83,1days\\ \tau_{\frac{1}{2}}=27,7days\\\\\\ N(t)=0,25mg*(\frac{1}{2})^{\frac{83,1}{27,7}}=0,25mg*(\frac{1}{2})^{3}=0,25mg*\frac{1}{8}=0,03125mg$