A student investigates how the radiation from a radioactive source changes over time. The table below shows the results from the detector used by the student:
| Time / minutes | Measured count rate / counts per minute |
|---|---|
| 0 | 500 |
| 3.0 | 260 |
| 6.0 | 140 |
| 9.0 | 80 |
The half-life of the source is known to be exactly 3.03.03.0 minutes.
Explain why the measured count rate after each 3.03.03.0-minute interval is always greater than half of the previous measured count rate, and calculate the constant background radiation count rate.
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.