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State Heisenberg'S Uncertainty Principle. Show that Electron Doesn'Texist in the Nucleus.Find the Accuracy in the Position of an Electron Moving with Speed 350 M/Sec with Uncertainty of 0.01%. - Applied Physics 1


State Heisenberg's Uncertainty Principle. Show that electron doesn'texist in
the nucleus.Find the accuracy in the position of an electron moving with speed 350
m/sec with uncertainty of 0.01%.

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Heisenberg'suncertainty principle states that one can not measure position and
moment of the moving particle exactly.Thus,the inaccuracies Δx and Δp in the
simultaneous determination of the position'x' and momentum 'p'respectively of a particle are related as 


Where ħ=h/2π, h being Planck's constant.

Non existence of electron inside the nucleus.

If the electromagnetic is inside the nucleus of radius of the other of10-15m,the maximum
uncertainty in the position of electron will be of the order of its radius


From the limiting condition of Heisenberg's uncertainty principle,



Now,Δpmin= mΔvmin

Hence,   Δvmin=Δpmin/m=1.055×10-19/9.1×10-31


As    Δvmin<v     v>1.159×1011 m/a>c

Therefore, the electron behaves as are lativistic particle.

The relativistic energy of the electronis

E=√mo 2c4+p2c2

Since,the actual momentum of the electronp >>Δpmin,p2c2>>mo

mass energy of the electron the value of which is 0.511MeV.Hence,


Assuming p=Δpmin,the least energy that an electron should posses within a nucleus

is given by


=3.165x10-11J  Emin=3.165×10-11/1.6×10-19=197MeV

Inreality, the only source of generation of electron within a nucleus is the process of
decay.The maximum kinetic energy possessed by the electrons during β-decay is about100 KeV.This shows that an electron can not exist within a nucleus

Numerical Solutlon :

Data :v=350m/sec,Δv/v=0.01

Formula: Δx•Δp≥ħ

Calculations: Δx.m.Δv≥ħ



Answer: Minimum uncertainty in position is 3.314×10-3m

Concept: Introduction to Quantum Mechanics
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