Moderate

When an electron is moving with velocity of 2.188 x 10^6 ms-1 in the first orbit of Bohrs model of hydrogen. The de Broglie wavelength of electron is______________?

Correct answer: A. 0.33 nm

  • A. 0.33 nm
  • B. 0.34 nm
  • C. 0.35 nm
  • D. 0.36 nm

Explanation

The de Broglie wavelength is λ = h/mv = (6.626 x 10^-34 J s)/[(9.109 x 10^-31 kg)(2.188 x 10^6 m/s)] = 3.33 x 10^-10 m. Since 1 nm = 10^-9 m, λ = 0.333 nm, which rounds to 0.33 nm. The likely mistake is choosing 0.36 nm from rough rounding of the electron mass or velocity.

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