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Carbon Dating

Tutorial to help you answer this question

Use the equation we have derived for carbon dating, N(t) = N0 − 0.0001216 t, to answer the following question. It may be helpful to know that the half-life of 14C is 5700 years.
3.

Problem 3- Calculate the initial amount of 14C in a fossil

Approximately how many grams of 14C did an organism initially possess if there are 7 g remaining after 17,830 years?

   

Tutorial

In this problem we are asked to solve for the initial quantity of 14C or N0. We write our model,

N(t) = N0 e − 0.0001216 t.

We know that 7 g remain after 17,830 years so we write,

N(17830) = 7 ≈ N0 e(−0.0001216)· (17830) ≈ (0.11439) · N0

Solving for N0 we have,

N0 ≈ 7 / 0.11439 ≈ 61.2.

Therefore, an initial sample of approximately 61.2 g of 14C decays to 7 g after 17,830 years.

Again, in terms of the half-life, this answer makes sense since 30.6 g would remain after 5700 years, 15.3 g would remain after 11,400 years, and 7.65 g would remain after 17,100 years.

 

   
   
   
   
   

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