Nuclear Decay and Radioactivity (4E) Practice Test

A laboratory calibrates a $^{99\text{m}}\text{Tc}$ generator used for SPECT imaging. The isomeric transition is $^{99\text{m}}\text{Tc} \rightarrow ,^{99}\text{Tc} + \gamma$. The half-life is listed as 6.0 h. Based on the decay model, what prediction can be made about the decay rate over time in a sealed vial?

A laboratory prepares a sealed standard containing $^{60}\text{Co}$, which decays by $\beta^-$ emission to an excited state of $^{60}\text{Ni}$ followed by gamma emission. The half-life of $^{60}\text{Co}$ is 5.27 y. Based on the decay model, what outcome is most likely regarding the sequence of emissions?