A detector is used to monitor the emissions from a radioactive source over a period of 50 minutes.
The table shows the count rate from the source at different times.
| Time / minutes | Count rate / counts s−1\text{counts s}^{-1}counts s−1 |
|---|---|
| 0 | 800 |
| 10 | 600 |
| 20 | 450 |
| 30 | 335 |
| 40 | 250 |
| 50 | 190 |
What is the half-life of the source?
between 10 and 20 minutes
between 20 and 30 minutes
between 30 and 40 minutes
between 40 and 50 minutes
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.