A hospital patient has been given some 131I (half-life = 8.04 d) which decays at 4.2 times the acceptable level for exposure to the general public. How long must the patient wait for the decay rate to reach the acceptable level? Assume that the material merely decays and is not excreted by the body.

Question

Quizplus · Accepted Answer

The decay rate decreases by half every 8.04 days. To reduce the decay rate to 1/4.2 of its initial value, the patient must wait for approximately 2 half-lives (16.08 days), which is closest to 17 days.

A Hospital Patient Has Been Given Some 131I (Half-Life =