Physics

Problem

A sample of a radionuclide has an initial activity of

8000\ \text{counts s}^{-1}

. Its half-life is

3\,\text{h}

. What will be the activity after

9\,\text{h}

? a)

2000\ \text{counts s}^{-1}

1000\ \text{counts s}^{-1}

400\ \text{counts s}^{-1}

1250\ \text{counts s}^{-1}