The half-life of C-14 is 5700 years. If it took seven half lives for a sample of C-14 to decay completely, how many years would have gone by?
7*5700 = ?
Carbon-14 has a half-life of 5730
years
. In a plant fossil, you find that the
14
C
has decayed to 1/32.0 of the original amount. How long ago was this plant alive?
To calculate the time it takes for a sample of C-14 to decay completely, we need to know the half-life and the number of half-lives that have passed.
Given that the half-life of C-14 is 5700 years and it took seven half-lives for the sample to decay completely, we can determine the total time that has passed.
To calculate the time, we multiply the half-life by the number of half-lives. Let's calculate:
Time = Half-life x Number of half-lives
Time = 5700 years x 7
Time = 39,900 years
Therefore, if it took seven half-lives for a sample of C-14 to decay completely, 39,900 years would have gone by.