Radioactivity

RADIOACTIVITY:In 1896 Becquerel discovered that uranium gave out some type of radiations that could affects a photographic plate. In 1898,pi re curie and Marie curie succeed in extracting from pitch blend(a uranium ore) a new substance which was many millions of times more active in emitting radiations than uranium.They named this elements as radium. The substances which emit these radiations are known as radioactivity. The phenomenon of spontaneous emission of powerful radiations exhibited by the heavier elements found in nature is called natural radioactivity. On the other hand, the phenomenon of spontaneous emission of radiations from the elements much lighter than those occur by modern techniques or artificial transmutation of elements is known as artificial or induced radioactivity.Radioactivity is the spontaneous disintegration of nucleus of an atom from which may be emitted some or all the following radiations.

1. Alpha particles
2. Bi ta particles
   
3. Gama rays
   

The alpha particles radiations consist of stream of particles which are nus lie of helium atom, where as bi ta particles are electrons and Gama rays are electronegative waves of nuclear origin consisting of neutral particles. It should be remembered that the radioactive elements while radiating radiations is transformed into a new element which, of course, is again radioactive. this change is irreversible. The emission of radiations from radioactive substance is not instantaneous but it is a prolonged process other wise the phenomenon of radioactivity could not be discovered at all.