Iodine-131 has a half-life of eight days. How many half-lives have passed after 24 days?
A) one half-life
B) two half-lives
C) three half-lives
D) four half-lives
E) five half-lives

Question

Quizplus · Accepted Answer

To find out how many half-lives have passed, we can divide the time elapsed by the half-life:

24 days / 8 days/half-life = 3 half-lives

Therefore, the answer is C) three half-lives.

Iodine-131 Has a Half-Life of Eight Days