If a radioactive sample has half the radioactive atoms left after 20 years, what is its half-life?
1 Answer
May 31, 2014
The answer is 20 years.
A half life is the time taken for the radioactive particles in a sample to decay by half. It would, therefore, take another 20 years for the half life to reach 1/4 of what it originally was.
The decay series by half lives looks like this:
