Question

Strontium-90 has a half-life of about 28 years

After 112 years, how many grams of a 50 g sample will remain?

Answer 1

`\textit{Amount for Exponential Decay using Half-Life} \\\\ A=P\left( (1)/(2) \right)^{(t)/(h)}\qquad \begin{cases} A=\textit{current amount}\\ P=\textit{initial amount}\dotfill &50\\ t=years\dotfill &112\\ h=\textit{half-life}\dotfill &28 \end{cases} \\\\\\ A = 50\left( (1)/(2) \right)^{(112)/(28)}\implies A = 50\left( (1)/(2) \right)^4 \implies A = 3.125`