According to the following decay process, Cs decays into the unstable Ba whose then
decays into a stable isotope of La.
The initial activity of Cs-139 is 10 mCi. Cs and Ba have a half life of 9.5 min and 82.9
min. Find
a. When does the maximum activity of Ba occur? (30)
b. The value of Ba activity. (20)
c. The value of Cs and La activity (20)