Question

You have 80 grams of a radioactive kind of cesium. How much will be left after 4 years if its half-life is 2 years?

Answer 1

80 expired grams

Explanation:

if 1/2 life is 2 years

after 4 years

they are expired

Answer 2

After 2 years there would be 40g
So after 4 years there would be 20g