A farmer in China discovers a mammal hide that contains 37% of its original amount of C-14. Find the age of the mammal hide to the nearest year.

Respuesta :

Answer: 54678 years

Step-by-step explanation:

This can be solved by the following equation:

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

Where:

[tex]N_{t}=54\%=0.54[/tex] is the quantity of atoms of carbon-14 left after time [tex]t[/tex]

[tex]N_{o}=1[/tex] is the initial quantity of atoms of C-14 in the mammal hide

[tex]\lambda[/tex] is the rate constant for carbon-14 radioactive decay

[tex]t[/tex] is the time elapsed

On the other hand, [tex]\lambda[/tex] has a relation with the half life [tex]h[/tex] of the C-14, which is [tex]5730 years[/tex]:

[tex]\lambda=\frac{ln(2)}{h}=\frac{ln(2)}{5730 years}=1.21(10)^{-4} years^{-1}=0.000121 years^{-1}[/tex] (2)

Substituting (2) in (1):

[tex]0.54=1e^{-(0.000121 years^{-1}) t}[/tex] (3)

Applying natural logarithm on both sides of the equation:

[tex]ln(0.54)=ln(1e^{-(0.000121 years^{-1}) t})[/tex] (4)

[tex]-0.616=-(0.000121 years^{-1}) t[/tex] (5)

Isolating [tex]t[/tex]:

[tex]t=\frac{-0.616}{-0.000121 years^{-1}}[/tex] (6)

[tex]t=54677.68 years \approx 54678 years[/tex] (7)  This is the age of the mammal hide