Asian Sciences Olympiad 2015 — Division M, Level 3 (Years 7–9) Question 19

The initial activity of a radioactive isotope is 120 Bq and the half-life is 20 minutes. For a sample of the same isotope with twice the mass, the values would be:

| Choice | Initial Activitiy / Bq | Half Life / minutes |
|:--:|--:|--:|
| A | 120 | 20 |
| B | 240 | 20 |
| C | 60 | 20 |
| D | 120 | 40 |