The half-life of iodine-131 is 8 days. If a medical treatment involves a dose of 100. mg of iodine-131, how much of the isotope remains after 16 days?

Question

Quizplus · Accepted Answer

The half-life of iodine-131 is 8 days, which means that after 8 days, half of the initial amount (100 mg) remains, i.e. 50 mg. Another 8 days later (after a total of 16 days), half of that amount (50 mg) remains, i.e. 25 mg. Therefore, the answer is B, 25 mg.

The Half-Life of Iodine-131 Is 8 Days