Question

The half-life of cobalt-60 (used in

radiation therapy) is 5.26 years (actual
data). How much of a 200 g sample of
cobalt-60 will remain after 26.3 years?

Answer 1

6.25 gm left

Explanation:

Find the number of half lives in 26.3 years

26.3 / 5.26 = 5 half lives

(1/2) ^5 = 1/32 nd of the original will be left

1/32 * 200g = 6.25 gm left