Nature and Characteristics of Radioactive Emissions
The phenomenon of radioactivity arises because of the decay of unstable nuclei or certain element. 
The nature of the radiations emitted from a radioactive substance was investigated by Rutherford (1904)by applying electric and magnetic fields. When these radiation were subjected to electric or magnetic field, these were split into three types a, b and g –rays.
Characteristics of radioactive rays
| a-Ray | b-Ray | g-Ray |
| Charge and mass: It carries +2 charge and 4 unit mass. | It carries -1 charge and no mass. | It has no charge and negligible mass. |
Identity: Helium nuclei or helium ion or He2+. | Electron  | High energy raditons. |
| Action of magnetic field:Deflected towards the cathode. | Deflected to anode. | Not deflected. |
| Velocity: 1/10th to that of light. | Same as that of light. | Same as that of light. |
| Ionizing power: Very high nearly 100 times to that of b-rays. | Low nearly 100 times to that of g-rays. | Very low. |
| Effect on ZnS plate: They cause luminescence. | Very little effect. | Very little effect. |
| Penetrating power: Low | 100 times that of a-particles. | 10 times that of b-particles. |
| Range: Very small. | More than a-particles. | More |
| Nature of product: Product obtained by the loss of 1 a-particle has atomic number less by 2 units and mass number less by 4 units. | Product obtained by the loss of 1 b-particle has atomic number more by 1 unit, without any change in mass number. | There is no change in the atomic number as well as in mass number |