Radioactivity is the emission of energetic particles or waves from atoms. Natural radiation occurs when unstable nuclei transform to some other nucleus by emitting radiation. Induced radiation often occurs when electrons which have been excited lose energy in the form of X-rays or microwaves, as done in microwave ovens and radar.
Types of Radioactive rays
Rutherford seperated the radio active emissions into three by passing them through a strong electric field between two parallel plates.The three radioactive rays are α-rays,β -rays,γ -rays.
These rays get deflected towards the negative plate or they carry positive charge.The particles in these rays alpha particles contain helium nuclei.They are shot out from the radio active material at high velocities ranging from 1.4 × 109 to 1.7 × 109 cms per second