The activity of a certain isotope dropped from 3200 Ci to 800 Ci in 12.0 years.
What is the half-life of this isotope (in years)?
How many half lives have elasped in a sample with a half life of 2 hours after 18 hours?
Calculate the number of half lives that elapse after 18 hours if a sample has a half life of 2 hours.For the nuclear reaction described in the following question, give the chemical symbol and mass number of the missing product.
The beta decay of Y-90 yields a beta particle and _____________.