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A fossilized leaf is found to contain 10 micrograms of carbon-14 whereas a leaf of this type normally contains about 13.5 micrograms of carbon-14. Estimate the age of te fossilized leaf. (The half-life of carbon-14 is 5730 years)

 Dec 15, 2014

Best Answer 

 #1
avatar+23254 
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FA  =  IA · (1/2)t/h

where  FA  =  Final Amount  =  10                  IA  =  Initial Amount  =  13.5

              t  =  time (years)                                h  =  half-life (years)  =  5730

--->    10  =  13.5 · (1/2)t/5730

--->     0.74074  =  (1/2)t/5730                                (divide both sides by 13.5)

--->     log(0.74074)  =  log( (1/2)t/5730 )               (since the variable is in the exponent, find the log)

--->     log(0.74074)  =  (t/5730)·log(1/2)              (an exponent in a log comes out as a multiplier)

--->     5730·log(0.74074)  =  t·log(1/2)                 (multiply both sides by 5730)

--->    5730·log(0.74074)/log(1/2)  =  t                  (divide both sides by log(1/2)

--->     t  =        <calculator time!>

 Dec 15, 2014
 #1
avatar+23254 
+5
Best Answer

FA  =  IA · (1/2)t/h

where  FA  =  Final Amount  =  10                  IA  =  Initial Amount  =  13.5

              t  =  time (years)                                h  =  half-life (years)  =  5730

--->    10  =  13.5 · (1/2)t/5730

--->     0.74074  =  (1/2)t/5730                                (divide both sides by 13.5)

--->     log(0.74074)  =  log( (1/2)t/5730 )               (since the variable is in the exponent, find the log)

--->     log(0.74074)  =  (t/5730)·log(1/2)              (an exponent in a log comes out as a multiplier)

--->     5730·log(0.74074)  =  t·log(1/2)                 (multiply both sides by 5730)

--->    5730·log(0.74074)/log(1/2)  =  t                  (divide both sides by log(1/2)

--->     t  =        <calculator time!>

geno3141 Dec 15, 2014

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