Structure Of Atom Ques 23
23. 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
[1998]
(a) $50$ $ kg \cdot s^{-1}$
(b) $80$ $ kg \cdot ms^{-1}$
(c) $8.0 \times 10^{-26}$ $ kg $ $ms^{-1}$
(d) $5.0 \times 10^{-26} $ $kg$ $ ms^{-1}$
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Answer:
Correct Answer: 23.(d)
Solution:
- (d) By Heisenberg uncertainty Principle $\Delta x \times \Delta p \geq \frac{h}{4 \pi}$ (which is constant)
As $\Delta x$ for electron and helium atom is same, thus momentum of electron and helium will not necessarily be same, and the uncertainty in momentum of helium atom is equal to $5 \times 10^{-26} $ $kg$ $ ms^{-1}$.
BETA
