The table shows the count rates obtained from four radioactive sources. The measurements were taken at noon on four consecutive weeks.
| Source | Week 1 count rate (c/s\text{c/s}c/s) | Week 2 count rate (c/s\text{c/s}c/s) | Week 3 count rate (c/s\text{c/s}c/s) | Week 4 count rate (c/s\text{c/s}c/s) |
|---|---|---|---|---|
| A | 6400 | 800 | 100 | 12 |
| B | 3200 | 1600 | 800 | 400 |
| C | 1600 | 1130 | 800 | 565 |
| D | 800 | 780 | 760 | 740 |
Which source has the shortest half-life?
Source A
Source B
Source C
Source D
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.