Question

The half-life of lead is 18 years. How long will it take for the sample of this substance to decay to 15%?a. Find your k

Answer 1

Solution

We are given

Half Life = 18 years

To solve for k

$\begin{gathered} 0.5=e^{-18k} \\ ln(0.5)=-18k \\ k=-\frac{ln(0.5)}{18} \\ k=0.0385081767 \end{gathered}$