Questions from Modern Physics

Q: If a proton and an electron have the same kinetic energy,

If a proton and an electron have the same kinetic energy, which has the longer de Broglie wavelength? Explain.

Q: Does a photon have a de Broglie wavelength? If so,

Does a photon have a de Broglie wavelength? If so, how is it related to the wavelength of the associated electromagnetic wave? Explain.

Q: Galaxies tend to be strong emitters of Lyman-α photons (

Galaxies tend to be strong emitters of Lyman-α photons (from the n = 2 to n = 1 transition in atomic hydrogen). But the intergalactic medium—the very thin gas between the galaxies— tends to absorb Lym...

Q: How might the energy levels of an atom be measured directly—

How might the energy levels of an atom be measured directly—that is, without recourse to analysis of spectra?

Q: Elements in the gaseous state emit line spectra with well-defined

Elements in the gaseous state emit line spectra with well-defined wavelengths. But hot solid bodies always emit a continuous spectrum—that is, a continuous smear of wavelengths. Can you account for th...

Q: a. An electron moves with a speed of 4.70

a. An electron moves with a speed of 4.70 * 106 m/s. What is its de Broglie wavelength? b. A proton moves with the same speed. Determine its de Broglie wavelength.

Q: In principle, does a hot gas have more mass than the

In principle, does a hot gas have more mass than the same gas when it is cold? Explain. In practice, would this be a measurable effect? Explain.

Q: Through what potential difference must electrons be accelerated if they are to

Through what potential difference must electrons be accelerated if they are to have a. the same wavelength as an x ray of wavelength 0.220 nm and b. the same energy as the x ray in part (a)?

Q: A beam of neutrons that all have the same energy scatters from

A beam of neutrons that all have the same energy scatters from atoms that have a spacing of 0.0910 nm in the surface plane of a crystal. The m = 1 intensity maximum occurs when the angle θ in Fig. 39....

Q: a. In an electron microscope, what accelerating voltage is needed

a. In an electron microscope, what accelerating voltage is needed to produce electrons with wavelength 0.0600 nm? b. If protons are used instead of electrons, what accelerating voltage is needed to p...