Half-Life

The half-life of a radioactive element is the time taken for half of the atoms initially present in the element to decay

Stable elements have long half-lives, while elements with short half-lives are unstable

If N is the number of atoms present initially, half of N = \(\left ( \frac{N}{2} \right)\)will decay at T \( \frac{1}{2} \)if the half-life of the atom is 10 seconds, in another 10 seconds, it will decay to \( \left(\frac{N}{4} \right)\), etc. The rate of decay of the radioactive element is directly proportional to the number of atoms of the material present. The unit of decay is Becquerel (B_q ).

Rate of decay \( \scriptsize \propto \)number of atoms initially