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