CBSE Class 11-science Answered

" Simultaneous and exact determination of the position and momentum of a sub atomic particle like electron moving with high speed is impossible .

 Heisenberg's uncertainty principle is one of the basic principles of wave mechanics and has to be taken note of while dealing with small particles in motion . If the uncertainty in the determination of the position of a small particle is given by  Δx and the uncertainty in its momentum is Δp then ,

                                       (Δ x)  ( Δp)  >   h/n∏     ( where n = 1,2,3,4,........)

   At any particular instant , we need to know the distance of electron from the nucleus as well as its momentum . For an electron revolving round the nucleus in an atom the value of n is nearly 4 . Hence we can write

                                    (Δ x)  ( Δp)  >   h/4∏

 Thus Heisenberg's uncertainty principle can be stated as

     The product of uncertainty in position and that in momentum of a micro particle moving high speed cannot be less than  h/4∏.