State and explain the laws of radioactive disintegration and hence define disintegration constant and half life period. Establish the relation between them.
According to law of radioactive decay rate of decay of radioactive atom at any instant is directly proportional to the number of atoms present at that instant.
Let N be the number of atoms present in a radioactive atom at any instant and dN br the number of atoms that disintegrates in a short interval DT. Then the rate of disintegration -dN/dt is proportional to N
That is, -dN/dt ?N
-dN/dt = lemda N
Where lemda is a constant and is called decay constant or disintegration constant
For a given element, the value of lemda is constant but for different elements it's value is different.
Half life:- it's defined as the time interval in which the nuclei of half of the atoms of the radioactive substance will disintegrate. It Is denoted by T.
T=0.693/lemda
Let N be the number of atoms present in a radioactive atom at any instant and dN br the number of atoms that disintegrates in a short interval DT. Then the rate of disintegration -dN/dt is proportional to N
That is, -dN/dt ?N
-dN/dt = lemda N
Where lemda is a constant and is called decay constant or disintegration constant
For a given element, the value of lemda is constant but for different elements it's value is different.
Half life:- it's defined as the time interval in which the nuclei of half of the atoms of the radioactive substance will disintegrate. It Is denoted by T.
T=0.693/lemda