A particular isotope has a half-life of 10 minutes. If we start with 2,000 atoms now, in a half hour we will have how many atoms left?
A) 2,000 atoms
B) 1,000 atoms
C) 500 atoms
D) 250 atoms
E) 125 atoms

Question

Quizplus · Accepted Answer

In a half hour (30 minutes), three half-lives will have passed (since each half-life is 10 minutes). After each half-life, the number of atoms is halved: 2000 -> 1000 -> 500 -> 250.

A Particular Isotope Has a Half-Life of 10 Minutes