"Carbon 14 (C-14), a radioactive isotope of carbon, has a half-life of 5730 ± 40 years. Measuring the amount of this isotope left in the remains of animals and plants is how anthropologists determine the age of samples. Example: The skeletal remains of the so-called Pittsburgh Man, unearthed in Pennsylvania, had lost 82% of the C-14 they originally contained. Determine the approximate age of the bones assuming a half-life of 5730."

Respuesta :

Answer:

The age of the bones is approximately 14172 years.

Explanation:

The age of the bones can be determinated using the following decay equation:

[tex] N_{(t)} = N_{0}e^{-\lambda t} [/tex]   (1)

Where:

N(t): is the quantity of C-14 at time t

No: is the initial quantity of C-14  

λ: is the decay rate      

t: is the time

First, we need to find λ:

[tex] \lambda = \frac{ln(2)}{t_{1/2}} [/tex]

Where:

t(1/2): is the half-life of C-14 = 5730 y

[tex] \lambda = \frac{ln(2)}{5730 y} = 1.21 \cdot 10^{-04} y^{-1} [/tex]

Now, we can calculate the age of the bones by solving equation (1) for t:

[tex] t = \frac{-ln(\frac{N_{(t)}}{N_{0}})}{\lambda} [/tex]

We know that the bones have lost 82% of the C-14 they originally contained, so:

[tex]N_{t} = (1 - 0.82)N_{0} = 0.18N_{0}[/tex]

[tex]t = \frac{-ln(0.18)}{1.21 \cdot 10^{-04} y^{-1}}[/tex]

[tex]t = 14172 y[/tex]

Therefore, the age of the bones is approximately 14172 years.

I hope it helps you!