radioactive activity

Question

A device used in radiation therapy for cancer contains 0.79 g of cobalt-60 (59.933 819 u). The half-life of this isotope is 5.27 yr. Determine the activity (in Bq) of the radioactive material.

Answer 1

Hey Aly,

Here I think this equation for activity is the most useful:

R = 0.693*N/(t_half-life)

1. N is the number of radioactive nuclei in the sample. You can find this using the atomic mass and the mass of the radioactive sample, along with Avogadro's number.
2. Convert the given half-life into seconds, since 1 Bq = 1 decay/second

Hope this helps,

Chris