The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t_1/2 = 5,730 yr)

Question

Quizplus · Accepted Answer

The age of the corn can be calculated using the formula for radioactive decay: $ t = \frac{t_{1/2}}{\ln(2)} \times \ln(\frac{N_0}{N}) $. Here, $ N_0 = 16 $ dpm, $ N = 7 $ dpm, and $ t_{1/2} = 5730 $ years. Solving gives approximately 6,800 years.

The Carbon-14 Activity of Some Ancient Indian Corn Was Found