Question

One-eighth of an original radioactive sample will remain at the end of __________ half-lives

Answer 1

One eighth of an original radioactive sample will remain at the end of 3 half lives.

Answer 2

Answer:

One-eighth of an original radioactive sample will remain at the end of THREE half-lives

Explanation:

As we know that half life is defined as the time after which a radioactive nuclei will remain half in the number as we compare it with the initial amount present in the sample.

So here let say initially sample contains N number of radioactive atoms

so after one half life we will have "N/2" present in that sample

after 2nd half life the number of nuclei again becomes half of the remaining

$N_1 = \frac{N}{4}$

now after 3rd half life we can say

$N_2 = \frac{N}{8}$

so here correct answer will be

One-eighth of an original radioactive sample will remain at the end of THREE half-lives