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ale4655 [162]
2 years ago
9

Element X decays radioactively with a half life of 12 minutes. If there are 200

Mathematics
1 answer:
PolarNik [594]2 years ago
8 0

\textit{Amount for Exponential Decay using Half-Life} \\\\ A=P\left( \frac{1}{2} \right)^{\frac{t}{h}}\qquad \begin{cases} A=\textit{current amount}\dotfill &20\\ P=\textit{initial amount}\dotfill &200\\ t=\textit{elapsed time}\\ h=\textit{half-life}\dotfill &12 \end{cases} \\\\\\ 20=200\left( \frac{1}{2} \right)^{\frac{t}{12}}\implies \cfrac{20}{200}=\left( \frac{1}{2} \right)^{\frac{t}{12}}\implies \cfrac{1}{10}=\left( \frac{1}{2} \right)^{\frac{t}{12}}

\log\left( \cfrac{1}{10} \right)=\log\left[ \left( \frac{1}{2} \right)^{\frac{t}{12}} \right]\implies \log\left( \cfrac{1}{10} \right)=t\log\left[ \left( \sqrt[12]{\frac{1}{2}} \right) \right] \\\\\\ \cfrac{\log\left( \frac{1}{10} \right)}{\log\left[ \left( \sqrt[12]{\frac{1}{2}} \right) \right]}=t\implies \implies \stackrel{mins}{39.9}\approx t

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