The table below gives the count-rate obtained from a sample of a radioactive isotope over a period of 100 minutes.
| Time / minutes | 0 | 20 | 40 | 60 | 80 | 100 |
|---|---|---|---|---|---|---|
| Count-rate / s−1\text{s}^{-1}s−1 | 600 | 356 | 212 | 125 | 74 | 44 |
From this table, estimate the half-life of the radioactive isotope.
144 exam-style questions on CIE IGCSE Physics 5.2.4a Half-life. Each one has a worked solution and a mark scheme showing where the marks go.