What is the mass of a particle with a wavelength of \(3.313 Å\) moving with a speed of \(2.0 \times 10^8…

What is the mass of a particle with a wavelength of \(3.313 Å\) moving with a speed of \(2.0 \times 10^8 \mathrm{~ms}^{-1}\) ?
  1. \(1.0 \times 10^{-28} \mathrm{~kg}\)
  2. \(2.0 \times 10^{-32} \mathrm{~kg}\)
  3. \(1.0 \times 10^{-32} \mathrm{~kg}\)
  4. \(2.0 \times 10^{-28} \mathrm{~kg}\)

Solution

According to de-Broglie relation: \(\lambda=\frac{h}{m v}\) where, \(h=\) Planck's constant \(=6.626 \times 10^{-34} \mathrm{Js}\) \(v=\) speed of moving particle \(m=\) mass of moving particle \(\lambda=\) wavelength of particle. Thus, \(m=\frac{h}{\lambda \times v}\) Given, Speed (velocity) of moving particle \((v)=2 \times 10^8 \mathrm{~m} / \mathrm{s}\) Wavelength of moving particle \((\lambda)=3.313 Å\) \(=3313 \times 10^{-10} \mathrm{~m}\) \(\begin{aligned} \therefore \quad m & =\frac{6.626 \times 10^{-34}}{3.313 \times 2 \times 10^8 \times 10^{-10}} \\ m & =1 \times 10^{-32} \mathrm{~kg} \end{aligned}\) Hence, option (c) is correct.

Asked in: AP EAMCET 2019 (23 Apr Shift 1)

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