Structure of Atom - Result Question 30

####32. Uncertainty in position of an electron (. mass .=9.1×1028g) moving with a velocity of 3×104cm/s accurate upto 0.001 will be (use h/4(π) in uncertainty expression where h=6.626×1027 erg-second)

[1995]

(a) 1.93cm

(b) 3.84cm

(c) 5.76cm

(d) 7.68cm

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Solution:

  1. (a) Given mass of an electron (m)=9.1×1028g; Velocity of electron (v)=3×104cm/s;

Accuracy in velocity =0.001;

Actual velocity of the electron

(Δv)=3×104×0.001100=0.3cm/s.

Planck’s constant (h)=6.626×1027 erg-sec. Uncertainty in the position of the electron

(Δx)=h4πmΔv=6.626×1027×74×22×(9.1×1028)×0.3=1.93cm



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