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 $ $ms^{-1}$

(b) $80$ $ kg$ $ ms^{-1}$

(c) $8.0 \times 10^{-26}$ $ kg $ $ms^{-1}$

(d) $5.0 \times 10^{-26} $ $kg$ $ ms^{-1}$

Show Answer

Answer:

Correct Answer: 23.(d)

Solution:

  1. (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}$.