#### Topics: Radionuclide - Wikipedia

Radioactive isotopes, such as 14 C, decay exponentially. The half-life of an isotope is defined as the amount of time it takes for there to be half the initial amount of the radioactive isotope present.

For example, suppose you have * N 0 * grams of a radioactive isotope that has a half-life of * t ** years. Then we know that after one half-life (or * t ** years later), you will have

We can use our our general model for exponential decay to calculate the amount of carbon at any given time using the equation,