If the position of the electron was measured with an accuracy of +0.002 nm . the uncertainty in the momentum…

If the position of the electron was measured with an accuracy of +0.002 nm . the uncertainty in the momentum of it would be (in $\left.\mathrm{kg} \mathrm{ms}^{-1}\right)\left(\mathrm{h}=6.626 \times 10^{-34} \mathrm{~J} \mathrm{~s}\right)$
  1. $2.637 \times 10^{-23}$
  2. $2.637 \times 10^{-24}$
  3. $8.283 \times 10^{-23}$
  4. $8.283 \times 10^{-24}$

Solution

Heisenberg uncertainty principle, $\Delta x \cdot \Delta p=\frac{h}{4 \pi}$ $\begin{aligned} & \Delta \mathrm{x}=2 \times 10^{-3} \mathrm{~nm} \\ & \Delta \mathrm{x}=2 \times 10^{-3} \times 10^{-9} \mathrm{~m} \quad\left[1 \mathrm{~nm}=10^{-9} \mathrm{~m}\right] \\ & \therefore \quad \Delta \mathrm{x}=2 \times 10^{-12} \mathrm{~m} \\ & \mathrm{~h}=6.626 \times 10^{-34} \mathrm{Js} \\ & {\left[1 \mathrm{~J}=1 \mathrm{~kg} \mathrm{~m}^2 \mathrm{~s}^{-2}\right]} \\ & \therefore \quad \Delta x \cdot \Delta p=\frac{1}{4 \pi} \\ & \Delta \mathrm{p}=\frac{\mathrm{h}}{4 \pi . \Delta \mathrm{x}}=\frac{6.626 \times 10^{-34} \mathrm{Js}}{4 \times 3.14 \times 2 \times 10^{-12} \mathrm{~m}} \\ & =0.2637 \times 10^{-22} \mathrm{~kg} \mathrm{~ms}^{-1} \\ & =2.637 \times 10^{-23} \mathrm{~kg} \mathrm{~ms}^{-1} \end{aligned}$

Asked in: AP EAMCET 2024 (23 May Shift 1)

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