Many radioisotopes have important industrial, medical, and
research applications. One of these is 60Co, which has a half-life
of 5.20 years and decays by the emission of a beta particle (energy
0.310 MeV) and two gamma photons (energies 1.17 MeV and 1.33 MeV).
A scientist wishes to prepare a 60Co sealed source that will have
an activity of at least 13.7 Ci after 37.0 months of use. If the
activity is 13.7 Ci, how many 60Co atoms are in the...