The table shows the results of an experiment to find the half-life of a radioactive substance.
| Time (sss) | Count rate (counts/s\text{counts/s}counts/s) |
|---|---|
| 0 | 240 |
| 80 | 170 |
| 160 | 120 |
| 240 | 85 |
| 320 | 60 |
What is the half-life of the substance?
80 seconds80\text{ seconds}80 seconds
160 seconds160\text{ seconds}160 seconds
240 seconds240\text{ seconds}240 seconds
320 seconds320\text{ seconds}320 seconds
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.