The ratio of carbon-14 to carbon-12 in the shaft of a wooden arrow, unearthed when a foundation was being dug for a new house, is 56.0% of the same ratio in a growing tree today. Assuming the ratio of carbon-14 to carbon-12 in the atmosphere has been constant, calculate the age of the arrow. The half-life of carbon-14 is 5730 years. The arrow is _______ years old Numeric Answer:

Respuesta :

Answer:

The wooden arrow is  [tex]t = 4793 \ years[/tex]  old

Explanation:

From the question we are told that

  The ratio of carbon -14 to carbon- 12  is  [tex]n = 56.0[/tex]%

   The half - life of carbon 14 is [tex]t_h = 5730 \ years[/tex]

Generally half-life is mathematically evaluated as

       [tex]t_h = \frac{ln 2}{\lambda }[/tex]

Where  [tex]\lambda[/tex] is the decay constant

    making [tex]\lambda[/tex]  the subject of the formula

          [tex]\lambda = \frac{ln2 }{5730}[/tex]

Now the age of the  wooden arrow can be mathematically obtained

       [tex]t =\frac{1}{\lambda } * ln (\frac{Z_o}{Z} )[/tex]

 The initial amount of [tex]Carbon -14[/tex] is  [tex]Z_0 = 1[/tex]

The amount [tex]Carbon -14[/tex]  remaining in the  wooden arrow is

           [tex]Z = 0.56[/tex]%

substituting values

              [tex]t = \frac{5730}{ln 2} * ln(\frac{1}{0.56} )[/tex]

              [tex]t = 4793 \ years[/tex]

     

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