Question

Radio carbon dating is done by estimating in specimen

• A. the amount of ordinary carbon still present
• B. the amount of radio carbon still present
• C. the ratio of amount of $^{14}C_{6} \, to ^{12}C_{6}$ still present
• D. the ratio of amount of $^{12}C_{6} \, to \, ^{14}C_6$ still present

Answer 1

Answer: (C)

the ratio of amount of $^{14}C_{6} \, to ^{12}C_{6}$ still present

Answer 2

Radiocarbon dating relies on a simple natural phenomenon. As the earth's upper is bombarded by cosmic radiation, atmospheric nitrogen is broken down into an unstable isotope of carbon-carbon $14( C -14)$. The unstable isotope is brought to earth by atmospheric activity, such as storms, and becomes fixed in the biosphere. Because it reacts identically to $C-12$ and $C-13, C-14$attached to complex organic molecules through photosynthesis in plants and becomes their molecular makeup. Animals eating those plants in turn absorb carbon- 14 as welll as stable isotopes. This process of ingesting C- 14 continues as long as the plant or animal remains alive. The C-14 within an organism is continually decaying into stable carbon isotopes, but organism is absorbing more $C-14$ during its life, the ratio of $C -14$ to $C -12$ remains about same as the ratio in the atmosphere. When the organism dies, the ratio of C-14 within its carcass begins to gradually decrease.