Half-life of carbon-14 is 5730 years. A piece of wood that contained 0.200g of Carbon-14 when it was alive now contains 0.0125g of Carbon-14. How old is the piece of wood? 5730 years old 11460 years old 17190 years old 22920 years old?

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Answer 1 · 2016-09-11T19:48:08

22920

#(1/2)^(t/5730)(I)=A#

I = initial amount, A = current amount, t = years

I=0.200g, A= 0.0125g, solve for t

#(1/2)^(t/5730)(0.200)=0.0125#

#(1/2)^(t/5730)=0.625#

#log_(1/2)((1/2)^(t/5730))=log_(1/2)0.0625#

#t/5730=4#

#t=22920#