(a) A sample is being dated by the radiocarbon technique. If the sample were unc
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Question
(a) A sample is being dated by the radiocarbon technique. If the sample were uncontaminated, its activity would be 0.033 Bq per gram of carbon. Find the true age (in years) of the sample. (b) Suppose the sample is contaminated, so that only 98.0% of its carbon is ancient carbon. The remaining 2.0% is fresh carbon, in the sense that the 6C14 it contains has not had any time to decay. Assuming that the lab technician is unaware of the contamination, what apparent age (in years) would be determined for the sample? Carbon-14 has a half-life of 5730 years, and an activity of 0.23 Bq per gram of carbon in a living organism.Explanation / Answer
(a)
Intial activity = Ao = 0.23 Bq / gm
Activity after time t = At = 0.064 Bq / gm
? = disntegration constant = 0.693 / T1/2
= 0.693 / 5730
= 1.20 x10-4
It is known by the formula
At = Ao e -?t
e -?t = (At/ Ao) = 0.2783
log ( e -?t ) = log(0.2783)
-?t = -0.5556
t = 0.5556 / 1.20x10-4
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