Question

Radioactive carbon-14 has a half-life of 5730 years. The remains of an animal are found 20,000 years after it died. About what percentage of the original amount of carbon-14 (when the animal was alive) would you expect to find?

Answer 1

Approximately 8.9% of the original amount of carbon-14 would be expected to remain in the remains of an animal found 20,000 years after it died, due to the half-life of C-14 being 5,730 years.

Step-by-step explanation:

The half-life of carbon-14 (C-14) is 5,730 years, meaning after this time, half of the original amount of C-14 will have decayed. To calculate what percentage of C-14 remains in a sample after 20,000 years, we can use the formula remaining percentage = (1/2)^(elapsed time / half-life).

First, we must determine how many half-lives have passed:
20,000 years / 5,730 years per half-life ≈ 3.49 half-lives.

Next, we calculate the remaining C-14:
(1/2)^3.49 ≈ 0.089 or 8.9%.

Therefore, we can expect to find approximately 8.9% of the original amount of C-14 in the remains of the animal.