Questions
Question 1
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State the de Broglie wavelength relation.
Question 2
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What happens to a particle's de Broglie wavelength when its momentum increases?
Question 3
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Why can electrons diffract from crystals?
Question 4
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An electron has momentum \(2.00\times10^{-24}\,\mathrm{kg\,m\,s^{-1}}\). Find its de Broglie wavelength.
Question 5
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A particle has de Broglie wavelength \(1.50\times10^{-10}\,\mathrm m\). Find its momentum.
Question 6
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An electron is accelerated from rest through \(100\,\mathrm V\). Find its kinetic energy in electronvolts and joules.
Question 7
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An electron is accelerated through \(150\,\mathrm V\). Estimate its nonrelativistic de Broglie wavelength.
Question 8
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A nonrelativistic electron's kinetic energy is quadrupled. By what factor does its de Broglie wavelength change?
Question 9
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Use \(K=p^2/(2m)\) to derive \(\lambda=h/\sqrt{2mK}\).
Question 10
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A crystal has plane spacing \(0.200\,\mathrm{nm}\). Electrons of wavelength \(0.100\,\mathrm{nm}\) scatter from it. Find the first-order Bragg angle.
Question 11
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Derive the wavelength of an electron accelerated from rest through potential difference \(V\).
Question 12
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What accelerating voltage gives an electron a nonrelativistic wavelength of \(0.100\,\mathrm{nm}\)?
Question 13
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A proton and an electron have the same speed. Which has the shorter de Broglie wavelength?
Question 14
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A proton and an electron have the same nonrelativistic kinetic energy. Which has the shorter de Broglie wavelength?
Question 15
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Why are macroscopic matter waves usually unobservable?
Question 16
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Show that the de Broglie relation gives a standing-wave condition for a circular orbit.
Question 17
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Explain why observing electron diffraction supports the wave-particle model rather than a purely particle model.
Question 18
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An electron wavelength is comparable to atomic spacing. Explain why this matters for microscopy.
Question 19
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A nonrelativistic electron wavelength calculation gives a speed close to \(c\). What should you change?
Question 20
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Derive how electron wavelength scales with accelerating voltage and state the physical meaning.