¹³¹I,which has a half- life time of 8 days,is used in nuclear medicine to monitor the hormone production in the thyroid in a patient.A sample of ¹³¹I containing 5 * 10¹⁰ atoms is produced in a nuclear reactor.Due to the short half- life time,the sample emits less radiation with time.However,it is usable as long as there are at least 1.25 * 10^{10 131}I atoms present.What is the maximum time before the sample is no longer usable?

Question

Quizplus · Accepted Answer

The half-life of the substance is 8 days, meaning the amount of substance halves every 8 days. Starting with 5x10^10 atoms, it will take two half-lives (16 days) to reduce to 1.25x10^10 atoms, making 16 days the maximum time before the sample is no longer usable.

131I,which Has a Half- Life Time of 8 Days,is Used

¹³¹I,which Has a Half- Life Time of 8 Days,is Used