Question

226Ra has a half-life of 1599 years. How much is left after 1000 years if the initial amount was 10 g?

Answer 1

$\bf \textit{Amount for Exponential Decay using Half-Life}\\\\ A=P\left( \frac{1}{2} \right)^{\frac{t}{h}}\qquad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{initial amount}\to &10\\ t=\textit{elapsed time}\to &1000\\ h=\textit{half-life}\to &1599 \end{cases} \\\\\\ A=10\left( \frac{1}{2} \right)^{\frac{1000}{1599}}$