A radioactive material has a half life of 20 seconds.If the initial amount of material is G grams,how much will be left at the end of one minute?

Question

Quizplus · Accepted Answer

One minute is equal to 60 seconds.

In one half-life (20 seconds), the amount of material reduces by half. Therefore, after 60 seconds, the material will go through 3 half-lives:

1st half-life: G/2 grams left 
2nd half-life: (G/2)/2 = G/4 grams left 
3rd half-life: (G/4)/2 = G/8 grams left

Therefore, the answer is D) G/8.

A Radioactive Material Has a Half Life of 20 Seconds