Electron frequency and wavelength

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Discussion Overview

The discussion revolves around the wave nature of particles, specifically focusing on the frequency and wavelength of electrons as described by de Broglie's hypothesis. Participants explore the relationships between frequency, wavelength, and momentum, and seek to clarify how these concepts apply to massive particles compared to massless particles like photons.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant states that the de Broglie wavelength of an electron is given by h / momentum, or h / (mv), and questions the relationship between frequency and wavelength for electrons.
  • Another participant asserts that de Broglie's prediction indicates that the wavelength of matter waves is analogous to that of photons, referencing the relationship f = c/lambda.
  • A participant challenges the previous assertions, arguing that the frequency is tied to energy rather than wavelength and that combining wavelength and frequency does not yield the correct velocity for electrons.
  • One response clarifies that the relationship f = v_{phase} / lambda applies to particles with mass, suggesting that the phase velocity must be considered.
  • A later reply acknowledges a mistake in earlier statements and emphasizes the correct relationship f = E/h, referencing the equations found in the provided Wikipedia link.

Areas of Agreement / Disagreement

Participants express differing views on the relationships between frequency, wavelength, and velocity for electrons, with no consensus reached on the correct interpretation or application of these concepts.

Contextual Notes

Participants highlight the need to distinguish between phase velocity and group velocity when discussing the wave properties of particles, indicating potential limitations in the initial claims made.

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Hi, I'm studying the wave nature of particles.

My book says that the de broglie wavelength of an electron is h / momentum, or h / (mv).
I also have that E = hf = momentum2/(2m) = 1/2 mv2.
I know that for a photon the frequency is speed of light / wavelength.


I'm wondering why the frequency for an electron is not 1/ wavelength. Is there any equation relating f and lambda for a particle (electron)?

Thanks for any help.
 
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DeBroglie predicted the wavelength of matter waves would be the same as for the photon.
The releatonship you want is the one you stated: f = c/lambda

Experimental confirmation is discussed here:
http://en.wikipedia.org/wiki/DeBroglie_wavelength
 
Naty's answer seems very wrong to me. The wavelength of a particle is tied to its momentum. The frequency is related to its energy. When you combine the wavelength and frequency to get the apparent velocity of the electron, the answer comes out wrong. You don't get the correct velocity.

The resolution of this paradox comes from a careful analysis of the roles of phase velocity vs. group velocity.
 
Naty1 said:
The releatonship you want is the one you stated: f = c/lambda

If c is the speed of light, that works only for photons.

For particles with mass, [itex]f = v_{phase} / \lambda[/itex] which gives

[tex]v_{phase} = f \lambda = \left( \frac{E}{h} \right) \left( \frac{h}{p} \right)<br /> = \frac{E}{p} = \frac {\sqrt{(pc)^2 + (m_0 c^2)^2}}{p}[/tex]
 
Duh, seems wrong to me, too; right your guys are!..I should have posted f = E/h
the equations are right there in the wiki reference, too.
 

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