An archeologist finds that the decay rate in a piece of wood is 6.8% of the value expected in the fresh wood. Given carbon's half-life is 5730 years, how old is it? (Assume that the ratio of isotoopes in the atmosphere is Carbon 14/Carbon 12 = 1.3*10^-12 and has remained constant.)

Question

egenriether · Answer

First solve for lambda:  $$\ln (2)\div(half-life)$$ = 1.209 x10^-4 
Now the age is given by 
ln(0.068)/-lambda = 22227.5 years.
I wish my response was better annotated but the equation editor on this site sucks.

anonymous · Answer

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