The half-life of a radioactive isotope is 6.5 h.If there are initially 48 *10³² atoms of this isotope, the number of atoms of this isotope remaining after 26 h is: A)12 * 10³² B)6 * 10³² C)3 * 10³² D)6 * 10⁴ E)3 * 10²

Question

Quizplus · Accepted Answer

The number of half-lives in 26 hours is 26/6.5 = 4. After 4 half-lives, the number of atoms remaining is (1/2)^4 = 1/16 of the initial amount. Therefore, 48 x 10^32 / 16 = 3 x 10^32 atoms remain.

The Half-Life of a Radioactive Isotope Is 6