2. The counting rates listed below were obtained when the activity of a certain radioactive sample was measured at different times. Plot the decay curve on semilog paper and determine the half-lives and initial activities of the component activities. Time, hr Counting rate, counts/min Time, hr Counting rate, counts/min 3500 2520 0.0 19100 4.0 14500 11410 0.5 5.0 1.0 6.0 1835 1.5 2.0 9080 7345 8.0 985 10.0 530 3.0 4985 12.0 290