Structure of Atom - Result Question 28
####30. The position of both, an electron and a helium atom is known within $1.0 nm$. Further the momentum of the electron is known within $5.0 \times 10^{-26} kg ms^{-1}$. The minimum uncertainty in the measurement of the momentum of the helium atom is
(a) $50 kg ms^{-1}$
(b) $80 kg ms^{-1}$
(c) $8.0 \times 10^{-26} kg ms^{-1}$
(d) $5.0 \times 10^{-26} kg ms^{-1}$
[1998]
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Solution:
- (d) By Heisenberg uncertainty Principle $\Delta x \times \Delta p=\frac{h}{4 \pi}$ (which is constant) As $\Delta x$ for electron and helium atom is same thus momentum of electron and helium will also be same and the uncertainty in momentum of helium atom is equal to $5 \times 10^{-26} kg ms^{-1}$.
