Question

Americium-241 is a radioactive substance used in smoke detectors. The half life of americium is 432 years. If a smoke detector initially contains 1 gram of Americium 241, how much will remain in 1,296 years?

a
0.5 g
b
0.25 g
c
1.0 g
d
0.125 g

Answer 1

To find out how much Americium-241 will remain in 1,296 years, we need to determine how many half-lives have passed.

1,296 years / 432 years = 3

Since each half-life reduces the amount of americium by half, after 3 half-lives, the amount of americium remaining will be:

1 gram / 2^3 = 1 gram / 8 = 0.125 grams

Therefore, the answer is d) 0.125 g.