Question

The half-life period of a radioactive element is 20 days. What will be the remaining mass of 100 g of it after 60 days?

(a) 25 g
(b) 50 g
(c) 12.5 g
(d) 20 g

Answer 1

Correct option is (c) 12.5 g

60 days = 3 half-lives, i.e, n = 3;