Rate of Radioactive Decay

The spontaneous breaking up of the nucleus is known as radioactive disintegration or radioactive decay. Radioactive disintegration is found to obey the following two laws:

i) Atoms of all radioactive elements are undergoing spontaneous disintegration i.e., are constantly breaking to form fresh radioactive products with the emission of a, b and g - rays.

ii) The rate of breaking is not affected by external factors like temperature, pressure, chemical combination etc. but depends entirely on the law of chance, i.e., the number of atoms breaking per second at any instant is proportional to the number present. In other words, the quantity of a radioactive element which disintegrates in unit time is directly proportional to the amount of radioactive element present.