Carbon-14 dating is often used to find the age of human-era relics. The half-life of Carbon-14 is 5,730 years.

Question

Carbon-14 dating is often used to find the age of human-era relics. The half-life of Carbon-14 is 5,730 years.

If it is determined that 3 half lives go by, how many years has that been?

Enter your answer with units of years.

1.72×104

Years

Using the same sample from above, what percent of the original sample is left?

Answer 1

3 half lives x 5730 yrs/half life = 17,190 years = 1.72x10⁴ years

Fraction remaining = 0.5ⁿ where n = number of half lives that have elapsed = 3

Fraction remaining = 0.5³ = 0.125 = 12.5 % left