Question

. Carbon-14 is used to determine the time an organism was living. The amount of carbon-14 an organism has is constant with the atmosphere, but when an organism dies the carbon-14 decays at a half-life of 5,730 years. If an archeologist measured the amount of carbon-14 in an organism and it was 25% of the total amount of atmospheric C-14, what is the age of the organism?

Answer 1

The answer is 11460 years

Answer 2

The answer is 11460 years

Half-life (x) is the time period (t) divided by the number of half-lives (n):
x = t/n

The number of half-lives (n) can be calculated by using the formula:
(1/2)ⁿ = a
where a is decimal amount remaining

We have:
x = 5,730 years
a = 25% = 25/100 = 0.25
n = ?
t = ?

(1/2)ⁿ = a
(0.5)ⁿ = 0.25
(0.5)ⁿ = (0.5)²
n = 2

x = t/n
t = x * n
t = 5730 * 2
t = 11460 years