Chemistry Question?

[匿名]

2016-02-20 5:18 am

The diffraction of radiation can be used to determine the spacing between atoms. In practice, the wavelength of the radiation used should be restricted to a value which is of the same order of magnitude as the interatomic distances to be determined. Such experiments are commonly performed using X-rays (electromagnetic radiation), however a beam of subatomic particles, such as of neutrons or electrons, may also be used if their corresponding de Broglie wavelength is of the appropriate magnitude.

1) Calculate the de Broglie wavelength of a neutron (mn = 1.67493×10-27 kg) moving at one four hundredth of the speed of light (c/400).

2) Calculate the velocity of an electron (me = 9.10939×10-31 kg) having a de Broglie wavelength of 241.8 pm.

回答 (1)

andrew

2016-02-20 5:42 am

✔ 最佳答案

1)
momentum : m v = h / λ

de Broglie wavelength of the neutron, λ
= h / (mv)
= (6.62607 × 10⁻³⁴) / [(1.67493 × 10⁻²⁷) × (2.9979 × 10⁸ / 400)]
= 5.278 × 10⁻¹³ m
= 0.5278 × 10⁻¹² m
= 0.5278 pm

2)
momentum : m v = h / λ

velocity of the electron, v
= h / (m λ)
= (6.62607 × 10⁻³⁴) / [(9.10939 × 10⁻³¹) × (241.8 × 10⁻¹²)]
= 3.008 × 10⁻⁶ m/s

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