Question

The measurement of the electron position is associated with an uncertainty in momentum which is equal to $1\times 10^{-18} \,g \,cm \,s^{-1}$. The uncertainty in electron velocity is

• A. $1\times 10^{9}\, g\,cm \,s^{-1}$
• B. $1\times 10^{6}\,g\,cm \,s^{-1}$
• C. $1\times 10^{5}\,g\,cm\, s^{-1}$
• D. $1\times 10^{11}\,g\,cm\, s^{-1}$

Answer 1

Answer: (A)

Given, $\Delta p=1\times 10^{-18}\,g \,cm\, s^{-1}$ (uncertainty in momentum)
Mass =$9\times 10^{-28}g$
$\Delta p=m \Delta v$
$1\times 10^{-18}=9\times 10^{-28}\times \Delta v$(uncertainty in velocity)
$\Delta v=1\times 10^{9} cm\, s^{-1}$