College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 30

The half-life of 131 I is 8.04 days. (a) Convert the half-life to seconds. (b) Calculate the decay constant for this isotope. (c) Convert 0.500 Ci to the SI unit the becquerel. (d) Find the number of 131 I nuclei necessary to produce a sample with an activity of 0.500 Ci. (e) Suppose the activity of a certain 131 I sample is 6.40 Ci at a given time. Find the number of half-lives the sample goes through in 40.2 d and the activity at the end of that period.