Question

7. Carbon-14 has a half-life of 5,730 years. If a sample contained 70. mg originally, how much isleft after 17,190 years?

Answer 1

In order to calculate how much carbon-14 will be left after 17190 years, we can use the formula:

$P=P_0\cdot0.5^{\frac{t}{n}}$

Where P0 is the final amount after t years, P0 is the initial amount and n is the period of half-life.

So, using P0 = 70, t = 17190 and n = 5730, we have:

$\begin{gathered} P=70\cdot0.5^{\frac{17190}{5730}} \\ P=70\cdot0.5^3 \\ P=70\cdot0.125 \\ P=8.75 \end{gathered}$

Therefore there will be 8.75 mg of carbon-14.