Question:
The half-life for radioactive decay of 14C is 5730 years. An archaeological artifact containing wood had only 80% of the 14C found in a living tree. Estimate the age of the sample.
Solution:
Here, $k=\frac{0.693}{t_{1 / 2}}$
$=\frac{0.693}{5730}$ years $^{-1}$
It is known that,
$t=\frac{2.303}{k} \log \frac{[\mathrm{R}]_{0}}{[\mathrm{R}]}$
$=\frac{2.303}{\frac{0.693}{5730}} \log \frac{100}{80}$
= 1845 years (approximately)
Hence, the age of the sample is 1845 years.