Kinetics of nuclear disintegration

A radionuclide disintegrates at a rate which is a function only of the constitution of the nucleus unlike ordinary chemical processes, it cannot be influenced by any chemical or physical means, such as by changing the temperature. The disintegration of a nucleus, with the emission of radiation, is kinetically a first-order process in other words, the rate of disappearance of the isotope is proportional to the amount n present at any time  

The proportionality constant k is known as the decay or disintegration constant. Integration of this equation proceeds as follows  

In other words, the nucleus decays exponentially with time. The half-life t is defined as the time that it takes for half of the nuclei to undergo transformation, and is obtained from (12.4) by putting n = njl  

Some data for radioactive isotopes used in biology are collected in Table 12.2. 

The half-life of tritium, fH, is 12.4 years. calculate the decay constant in s L 

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