More accurate dates of the reigns of ancient Egyptian pharaohs have been determined recently using plants
that were preserved in their tombs. Samples of seeds and plant matter from King Tutankhamun’s tomb have
a C-14 decay rate of 9.07 disintegrations/min/g of C. How long ago did King Tut’s reign come to an end?

Please show how to achieve the answer. I do not know how to get the answer of 3350 years. Please explain what equations

Respuesta :

King Tut's reign came to an end at 3350 years ago

Further explanation

Carbon-14 is a radioactive isotope that can decay. This isotope can be used to determine how long ago an organism died by knowing the ratio from 12C to 14C

Can be formulated

[tex]\tt Nt=No\dfrac{1}{2}^{t/t1/2}[/tex]

Or we can use :

[tex]t=-\frac{1}{\lambda }\text{ln}\left(\frac{{N}_{t}}{{N}_{0}}\right)\longrightarrow t=-\frac{1}{\lambda }\text{ln}\left(\frac{{\text{Rate}}_{t}}{{\text{Rate}}_{0}}\right)[/tex]

The half-life of C-14, 5730 years, so the decay constant :

[tex]\tt \lambda =\dfrac{\text{ln 2}}{{t}_{1\text{/}2}}=\dfrac{0.693}{\text{5730 y}}=1.21\times {10}^{-4}}[/tex]

Assume the initial C-14 activity was 13.6  disintegrations/min/g of C

[tex]\tt t=-\dfrac{1}{\lambda }\text{ln}\left(\dfrac{{\text{Rate}}_{t}}{{\text{Rate}}_{0}}\right)=-\dfrac{1}{1.21\times {10}^{-4}}\text{ln}\left(\dfrac{9.07}{13.6}\right)=\text{3348}\approx 3350~y[/tex]