Carbon 14 is used to determine the age of organic material. The procedure 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)p^(1)`
`.^(14)C` is absorbed by living organisms during photosynthesis. 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)N + beta^(-)`
The half-life period of `.^(14)C` is 5730 years. The decay constant `(lambda)` can be calculated by using the following formula `lambda = (0.693)/(t_(1//2))`
The comparison of the `beta^(-)` activity of the dead matter with that of the carbon still in circulation enables measurement of the period of the isolation the material form the living cycle. The method however, ceases to be accurate ever periods longer than `30,000` years. The proportion of `.^(14)C` to `.^(12)C` living matter is `1:10^(12)`.
Which fo the following option is correct?

Options

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

Answer

C

Explanation

In living organism, `.^(14)C` content is constant (not carbon content) as the rate of absorption of `c^(14)` is equal to rate of disintegration of `.^(14)C`.
Carbon dating can be used to fing out the age of organic materic only .(not for finding the age of earth crust and rocks made of inorganic material)