Assuming two samples of radioisotopes both contain the same number of atoms, the activity of the shorter-half-life isotope would be initially ____ and decay ____.

Question

Quizplus · Accepted Answer

The activity (rate of decay) of a radioactive isotope is directly proportional to the number of radioactive atoms present in the sample. Therefore, assuming both samples contain the same number of atoms, the sample with the shorter half-life will have a higher initial activity because it has more decays per unit time than the longer-half-life sample. Additionally, the shorter-half-life isotope will decay more quickly (i.e. have a higher decay rate) because half of its atoms will decay in a shorter amount of time compared to the longer-half-life isotope.

Assuming Two Samples of Radioisotopes Both Contain the Same Number