a. A certain radioactive material emits gamma rays with energy 1 MeV. Another sample of radioactive material emits gamma rays with energy 10 keV. If both of these emit the same amount of energy per unit time, compare their activities.
b. A source of 198Au with a half-life of 2.69 days has an initial activity of 5 Ci. Calculate the activity after 4.0 days. Express this activity in Bq.