An animal fossil has 100 grams of carbon-14 initially within it. Knowing that these atoms radioactively decay to nitrogen-14 with a half-life of 5730 years, determine how much of the parent isotope and daughter isotope remain after 5 half-lives have transpired. How many years would have elapsed (in 5 half-lives)?

Question

An animal fossil has 100 grams of carbon-14 initially within it.  Knowing that these atoms radioactively decay to nitrogen-14 with a half-life of 5730 years, determine how much of the parent isotope and daughter isotope remain after 5 half-lives have transpired.  How many years would have elapsed (in 5 half-lives)?

xishem · Answer

Do you know what a half-life actually means? It is the amount of time it takes for exactly half of the substance to decay.

This means that after 1 half-life, one-half of the original substance will remain.

And after 5 half-lifes, 1/2 of 1/2 of 1/2 of 1/2 of 1/2 of the original substance will remain. Does that help?