How long will it take for 75% of the carbon-14 atoms in a biological sample to decay to nitrogen-14?

Question

Quizplus · Accepted Answer

The half-life of carbon-14 is approximately 5730 years. This means that in 5730 years, 50% of the carbon-14 atoms will have decayed. To reach 75% decay, we need one and a half half-lives (since 50% + 25% = 75%). Therefore, 5730 years * 1.5 = 8595 years. However, the correct calculation for 75% decay actually involves two half-lives, because after the first half-life (5730 years), 50% remains, and after the second half-life, half of that 50% (or 25% of the original) remains, totaling 75% decay. Thus, 5730 years * 2 = 11,460 years.

How Long Will It Take for 75% of the Carbon-14