12. A rat ingests an isotope having a physical half-life of 100 days and a biological half-life of 30 days. Three weeks later he is attacked by a cat and killed. A worker discovers the remains and sends a tissue sample to a laboratory for analysis. A count rate of 1600 counts s is measured from the tissue sample 85 days from the time the isotope was originally ingested by the rat. What would have been the count rate from an equal amount of tissue just after the isotope was consumed by the rat? (Assume the isotope was quickly distributed about the rat's tissues and that λb = 0 after death.) (A) 2360 counts/s (B) 4680 counts/s (C) 0 counts/s (D) 150 counts/s (E) 651 counts/s 13. Using a detector and a ruler, data was collected in order to determine the linear attenuation coefficient u. Plotting the data on the graph below, determine µ. Counts/min Thickness(cm) 10000 0 7800 0.5 6060 1 4700 1.5 3700 2 2870 2.5 2230 3 1740 3.5 1350 4

12. A rat ingests an isotope having a physical half-life of 100 days and a biological half-life of 30 days. Three weeks later he is attacked by a cat and killed. A worker discovers the remains and sends a tissue sample to a laboratory for analysis. A count rate of 1600 counts s is measured from the tissue sample 85 days from the time the isotope was originally ingested by the rat. What would have been the count rate from an equal amount of tissue just after the isotope was consumed by the rat? (Assume the isotope was quickly distributed about the rat's tissues and that λb = 0 after death.) (A) 2360 counts/s (B) 4680 counts/s (C) 0 counts/s (D) 150 counts/s (E) 651 counts/s 13. Using a detector and a ruler, data was collected in order to determine the linear attenuation coefficient u. Plotting the data on the graph below, determine µ. Counts/min Thickness(cm) 10000 0 7800 0.5 6060 1 4700 1.5 3700 2 2870 2.5 2230 3 1740 3.5 1350 4