An artifact contains one-fourth as much carbon-14 as the atmosphere. how old is the artifact
The half life of Carbon-14 is 5,730 years
To contain 1/4 of the value, 2 half-lives must have passed.
The artifact is: 2 x 5,730
= 11,460 years older than the atmosphere.
= 11,460 years
The initial amount of carbon-14 in this case was 1 whole; thus;
1 → 1/2 →1/4
To contain 1/4 of the value, 2 half-lives have passed.
But, 1 half life = 5,730 years
Therefore; The artifact is is therefore: 2 x 5,730
= 11,460 years