Complete Question:
Iodine-131 is a radioactive isotope with a half-life of 8 days. How many grams of a 64 g sample of iodine-131 will remain at the end of 24 days? (It's an example of a likely question. In the question given, the time is given in hours, which must be converted by days, 1 day = 24 hours).
Answer:
8 g.
Explanation:
The half-life is the time needed to the mass decay by half, thus, if the initial mass is M and the final mass is m:
m = M/2ⁿ
Where n is how much half-lives had passed, thus
n = time/(half-life time)
n = 24/8
n = 3
m = 64/2³
m = 64/8
m = 8 g
