A sample of iodine-131 has an activity of 200 mCi. If the half-life of iodine-131 is 8.0 days, what activity is observed after 16 days? 0.5 half lives
Step [1]: Determine the number of half lives.
x 128
5.88 x10-37
mci
16 days
128 half lives
2 half lives
80 half lives
1 day
Step [2]: Find the final activity.
50.0 mci
200. mci
200. mci
(initial activity)