Iodine-131, T_1/2 = 8

question 79

Multiple Choice

Iodine-131, t_1/2 = 8.0 days, is used in diagnosis and treatment of thyroid gland diseases. If a laboratory sample of iodine-131 initially emits 9.95 × 10¹⁸  particles per day, how long will it take for the activity to drop to 6.22 × 10¹⁷  particles per day?

• A) 2.0 days
• B) 16 days
• C) 32 days
• D) 128 days
• E) none of the above