Radioactivity: Half Lives

Definition: The Half Life of a radio active material is defined as te length of time it takes for one half the sample to undergo radioactive decay.This means that after one half life only half the origonal radioactive isotope remains. The other half of the material has decayed into other isotopes or other elements (depending on the type of decay).

The half life of radioactive isotopes is determined experimentally using a Geiger Counter.

Principle of operation of a Geiger Counter