An isotope used in cancer therapy has a half-life of

PHYSICS · Single correct · A Level · Physics · Nuclear physics · Nuclear physics

Problem

12\,\text{h}

. At the start of a treatment its activity is

1.0\,\text{Ci}

(

1\,\text{Ci}=3.7\times10^{10}\,\text{Bq}

). After some time its measured activity is

5.78\times10^{8}\,\text{Bq}

. How many hours have elapsed since the start? (a) 60\,h (b) 72\,h (c) 50\,h (d) 48\,h