CAPE Physics Unit 2 · 2018 · Paper 1 · Question Q44

A sample of radioactive material contains initially 2.0 \times 10^{18}\text{ atoms}. The material decays by \alpha-emission and has a half-life of 3.0 \times 10^{10}\text{ s}. The initial activity of the sample is

1. (A)4.6 \times 10^7\text{ Bq}
2. (B)1.5 \times 10^8\text{ Bq}
3. (C)2.0 \times 10^9\text{ Bq}
4. (D)2.3 \times 10^{11}\text{ Bq}