Question

If a radioactive material has a half-life of 15 y what fraction of the material will remain after 30 y

Answer 1

1/4

Step-by-step explanation

half life = 15 years

decay period = 30 years

The number of half-lives = 30 ÷ 15

= 2 half lives

1 ⇒(after 1st half life) ⇒ 1/2 ⇒ (after 2nd half life) ⇒ 1/4

The fraction that remained is 1/4.