If a radioactive element has a half-life of 704 million years,and the amount of parent material remaining is one-eighth of the original amount,the specimen is about
A)2,112,000,000 years old.
B)1,408,000,000 years old.
C)2,816,000,000 years old.
D)3,520,000,000 years old.

Question

Quizplus · Accepted Answer

The specimen is about 2,112,000,000 years old because it takes three half-lives to reduce to one-eighth (1/2^3) of the original amount, and with each half-life being 704 million years, three half-lives equal 2,112 million years (704 million years x 3).

If a Radioactive Element Has a Half-Life of 704 Million