(b)The half-life of a radioisotope is the amount of time it takes for the amount of time it takes for half the sample to decay.
A radioisotope decays and changes to an alternate element at a consistent rate. The rate is estimated in a unit called the half-life. This is the time span it takes for half of a given measure of the radioisotope to decay. This rate is dependably the same for a given radioisotope.