If 50% of a radioactive element remains after 4000 years, what is the half-life?

Question

a
1 half-life
b
2 half-lives
c
3 half-lives
d
4 half-lives

Answer 1

If 50% of a radioactive element remains after 4000 years, that indicates that one half-life has passed. In other words, the time it takes for the amount of a radioactive substance to decrease by half is called its half-life.

Therefore, the answer is:

a. 1 half-life