Physics

Problem

The activity of a 10.0 g sample of

^{99\text{m}}\text{Tc}

decreases from

4.0\times10^{5}\,\text{Bq}

5.0\times10^{4}\,\text{Bq}

in 18.0 h. Determine the half-life of

^{99\text{m}}\text{Tc}

, in hours.