Physics · May / June 2020 · Paper 11 · Question 39

$^{14}_{6}\text{C}$ is a natural radioactive isotope of carbon and is present in all living things. It has a half-life of 5700 years. How old is a bone that is found to have only $\frac{1}{4}$ of the natural proportion of $^{14}_{6}\text{C}$?

1. A5700 years
2. B11 400 years
3. C17 100 years
4. D22 800 years

As printed in the paper