Carbon 14 is used to determine the age of organic material. The procerdure is based on the formation of `.^(14)C` by neutron capture in the upper atmosphere.
`._(7)^(14)N + ._(0)^(1)n rarr ._(6)^(14)C + ._(1)n^(1)`
`.^(14)C` is abosorbed by living organisms during phostosythesis. The `.^(14)C` content is constant in living organisms once the plant or animal dies, the uptake of carbon dioxide by it ceases and the level of `.^(14)C` in the dead being, falls due to the decay which `.^(14)C` undergoes.
`._(6)^(14)C rarr ._(7)^(14)C + beta^(-)`
The half-life period of `.^(14)C` is 5770 years. The decay constant `(lambda)` can be calculated by using the following formula `lambda = (0.693)/(t_(1//2))`
The comparison fo the `beta^(-)` activity fo the dead matter with that of the carbon still in circulation enables measurement of the period of the isolation the materail form the living cycle. The method however, ceases to be accurate ever periods longer than `30,000` years. The proportaion of `.^(14)C` to `.^(12)C` living matter is `1:10^(12)`.
Which fo the following option is correct?

Options

A. In living organism, circulation of `.^(14)C` from atomsphere is high so the carbon content is constant in orginsm.
B. carbon dating can be used to find out the age of earth crust and rocks.
C. Radioactive absoption due to cosmic radiation is equal to the rate of radioactive decay, hence the carbon content remains constant in living organisms.
D. Carbon dating cannot be used to determine concentration of `.^(14)C` in dead beings.

Answer

`c`

Explanation

Rediaoactive absoption due to cosmic radiataction is equal to the rate of radioactive decay, hence the carbon content as the ratio of `.^(14)C` to `.^(12)C` remains constatn in living organisms.