SOLUTION: Use the fact that after 5715 years, a given amount of carbon-14 will have decayed to half the original amount to find the exponential decay model for carbon-14. In 1947, earthenwa

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Use the fact that after 5715 years, a given amount of carbon-14 will have decayed to half the original amount to find the exponential decay model for carbon-14. In 1947, earthenwa      Log On


   



Question 1029621: Use the fact that after 5715 years, a given amount of carbon-14 will have decayed to half the original amount to find the exponential decay model for carbon-14. In 1947, earthenware jars containing what are known as Dead Sea Scrolls were found by an Arab Bedouin herdsman. Analysis indicated that the scroll wrappings contained 76% of their original carbon-14. Estimate the age of the Dead Sea Scrolls.
Age in 1947 and age today.

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Use the fact that after 5715 years, a given amount of carbon-14 will have decayed to half the original amount to find the exponential decay model for carbon-14.
In 1947, earthenware jars containing what are known as Dead Sea Scrolls were found by an Arab Bedouin herdsman.
Analysis indicated that the scroll wrappings contained 76% of their original carbon-14.
Estimate the age of the Dead Sea Scrolls.
Age in 1947 and age today.
:
The radioactive decay formula
A = Ao*2^(-t/h), where
A = the amt remaining after t time
Ao = initial amt
t = time of decay
h = half-life of the substance
:
let Ao = 1
let A = .76
1 * 2^(-t/5715) = .76
Using natural logs
ln(2^(-t/5715)) = ln(.76)
log equiv of exponents
-t%2F5715ln(2) = ln(.76)
-t%2F5715+=+ln%28.76%29%2Fln%282%29
use you calc
-t%2F5715 = -.396
t = -.396 * 5715
t = 2263 yrs is the age of the Scroll in 1947
now their age is:
(2016-1947) + 2263 = 2332 yrs