Question #3f70e
1 Answer
Oct 18, 2017
25 mg will remain.
Four half lives are needed to take the sample down to 6.25 mg
Explanation:
This period of time is called the half-life because it represents the amount of time needed for half of the atoms in a radioactive sample to decay (thereby becoming a different element).
If one half life bring you to half the sample remaining, then a second half life will result in the decay of one-half of what remains of original sample.
In other words, one half of one half is one quarter of the original amount - 25 mg.
After three half lives, 12.5 mg remain, and after four half lives, 6.25 mg remain. And by the way, this will be not 1/6 of the original amount, but 1/16
