Carbon-14 has a half-life of 5,730 ± 40 years—i.e., half the amount of the radioisotope present at any given time will undergo spontaneous disintegration during the succeeding 5,730 years.

## What is a half-life in radiocarbon dating?

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 N0 grams of a radioactive isotope that has a half-life of t* years.

## What percentage of carbon-14 remains after 2 half-lives?

25 percent After two half-lives, 25 percent of the original carbon-14 atoms remain.