Heisenberg's Uncertainty Principle

Definition of Heisenberg's Uncertainty Principle


According to Heisenberg's uncertainty principle, it is not possible to determine precisely both the position and momentum (or velocity) of a moving microscopic particle, simultaneously with accuracy.


Mathematical Expression of Heisenberg's Uncertainty Principle

▵x .▵p => h / 4π

Where  ▵x is uncertainty with regard to the position and ▵p is uncertainty with regard to the momentum of the particle. If ▵x is very small ▵p would be large , that is , uncertainty with regard to momentum will be large. On the other side if we attempt to find out the momentum exactly the uncertainty with regard to position will be large.

Explanation of  Heisenberg's Uncertainty Principle

To determine the position of a small body like electron, it has to be illuminated with electromagnetic radiation. Low energy radiations like ordinary light waves cannot be used to illuminate a small body like electron, since the size of the electron is very small when compared with the wave length of ordinary light. Therefore to irradiate electrons, radiations with shorter wave length are used. When such a high energy radiation is allowed to fall on an electron its velocity changes by a large value. Consequently if we find the position of an electron precisely, there is always an uncertainty in finding the velocity of an electron simultaneously. Thus the determination of position and momentum of a moving electron precisely and simultaneously is impossible.