What is the number of half-lives needed for a radioactive element to decay to one-fourth of its original activity? (Choose the nearest number.)
A) 1
B) 4
C) 3
D) 5
E) 2

Question

Quizplus · Accepted Answer

After one half-life, the activity of a radioactive element is reduced to half its original level. After two half-lives, it is reduced to one-fourth. Therefore, it takes 2 half-lives to decay to one-fourth of its original activity.

What Is the Number of Half-Lives Needed for a Radioactive