# Heisenberg’s uncertainty principle

Heisenberg’s Uncertainty principle : “Simultaneous and exact determination of the position and momentum of a sub-atomic particle, like electron moving with high speed is impossible”.

If x and p represent the uncertainties in the position and momentum respectively. Then according to Heisenberg

x . p    ………….. (1)

The product of uncertainties in position (x) and momentum (p) of an electron cannot be less than .  It can be equal or greater than .

Since momentum  mass  velocity,  the equation (1) can be written as

m (v)

If the position is determined accurately  x = 0 and v = . That means the inaccuracy in measuring the velocity is . If velocity is determined accurately v = 0 and x = .

Significance of Heisenberg’s Uncertainty principle :

• This principle rules out the existence of definite paths or trajectories of electrons and other similar particles.
• This principle is significant only for the motion of microscopic objects and is negligible for that of macroscopic objects.
• In dealing with milligram size or heavier objects, the associated uncertainties are hard of any real consequence.