Question

You have 379,200 grams of a radioactive kind of samarium. How much will be left after 450 years if its half-life is 90 years?

Answer 1

The equation for the amount left after t years if half life is

`t_{(1)/(2)}`

and initial amount is A is,

`A^(\prime)=A((1)/(2))^{\frac{t_{}}{t_{(1)/(2)}}}`

Determine the amount left after 450 years.

`\begin{gathered} A=379200*((1)/(2))^{(450)/(90)} \\ =379200*((1)/(2))^5 \\ =11850 \end{gathered}`

Thus amount of samarium left after 450 years is 11850 grams.