Where Δ N is the number of decays that occur in time Δ t. Therefore, the number of radioactive nuclei decreases from N to \frac\\ Further, half of that amount decays in the following half-life. Half of the remaining nuclei decay in the next half-life. The time in which half of the original number of nuclei decay is defined as the half-life, t 1/2. Why use a term like half-life rather than lifetime? The answer can be found by examining Figure 1, which shows how the number of radioactive nuclei in a sample decreases with time.
In this section we explore half-life and activity, the quantitative terms for lifetime and rate of decay. This means they have shorter lifetimes, producing a greater rate of decay. For example, radium and polonium, discovered by the Curies, decay faster than uranium. However, some nuclides decay faster than others. Calculate age of old objects by radioactive dating.By the end of this section, you will be able to:
