Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
The half-life is the time it takes for half of the radioactive atoms in a sample to undergo radioactive decay.
Related terms
Decay constant: It is a measure of how quickly a radioactive substance decays. It is related to the half-life and can be used to calculate it.
Radioactive dating: This is a method used to determine the age of rocks or fossils by measuring the ratio of parent isotopes to daughter isotopes, using their known half-lives.
Nuclear fission: It is a process in which an atomic nucleus splits into two smaller nuclei, releasing energy and often producing additional neutrons.