What is a half-life?
the amount of time it takes for half of a radioactive substance to decay the amount of time it takes for all of a radioactive substance to decay
half the time it takes for a radioactive substance to break down
the reactive half of a radioactive substance
the amount of time it takes for half of a radioactive substance to decay the amount of time it takes for all of a radioactive substance to decay
half the time it takes for a radioactive substance to break down
the reactive half of a radioactive substance