Question

An archaeologist analyses the wood in a prehistoric structure and finds that $C^{14}$ (Half life = 5700 years) to $C^{12}$is only one- fourth of that found in the cells buried plants. The age of the wood is about.

• A. 5700 years
• B. 2850 years
• C. 11,400 years
• D. 22,800 years

Answer 1

Answer: (C)

11,400 years

Answer 2

$\frac{C_{14}}{C_{12}} = \frac{1}{4} = \left( \frac{1}{2} \right)^{t/5700} \Rightarrow \frac{t}{5700} = 2 \Rightarrow t = 11400\mspace{6mu} years$