Electron Speed: Measured & Calculated?

[acherentia]

My general science courses give various speeds for electrons to illustrate various examples. My preconception was that electrons always move very fast, but some of the examples from textbooks assume speeds that are a lot less than what I expected from an electron . Has the full range of possible speeds an electron can take been calculated or measured or both?

 

[Dale]

An electron, like any massive particle, can go from 0 to just under c. In "everyday" situations like electrical circuits there are two important velocities, the Fermi speed which is the typical instantaneous speed due to thermal motion (~10^6 m/s) and the drift velocity which is the average speed corresponding to an electrical current (~10^-4 m/s).

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html#c2

 

[acherentia]

That's an awesome answer, thanks!

 

[Dale]

You are very welcome!

 

[Bob S]

Experimental electron beam energies have ranged from fractions of an electron volt to ~50 GeV (at SLAC and the CERN 26-km-circumference LEP), Lorentz gammas up to ~100,000. One of the most beautiful electron-beam demonstrations I can remember is the undergraduate e/m Lorentz-force experiment, such as the 300-volt electron beam in a Helmholtz coil shown in this attachment.

https://www.physicsforums.com/attachment.php?attachmentid=22954&d=1263085690

Every undergraduate physics lab must do this experiment,

Bob S

 

[Per Oni]

An electron, like any massive particle, can go from 0 to just under c. In "everyday" situations like electrical circuits there are two important velocities, the Fermi speed which is the typical instantaneous speed due to thermal motion (~10^6 m/s) and the drift velocity which is the average speed corresponding to an electrical current (~10^-4 m/s).

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html#c2

From the site you referred to:

Because electrons are fermions and obey the Pauli exclusion principle, then at 0 K temperature the electrons fill all available energy levels up to the Fermi level.

Perhaps its nitpicking but why do you think Fermi speed due to thermal motion? As far as I understand Fermi speed is there at 0K and alters only slightly at room temperature.

 

[Bob S]

An electron, like any massive particle, can go from 0 to just under c. In "everyday" situations like electrical circuits there are two important velocities, the Fermi speed which is the typical instantaneous speed due to thermal motion (~10^6 m/s) and the drift velocity which is the average speed corresponding to an electrical current (~10^-4 m/s).

The electron velocity in a standard CRT (cathode ray tube) TV set with a 10,000 volt electron gun is about 5.8 x 10⁷ meters per second.

Bob S

 

[James Leighe]

The speed of light, because of zitterbewegung. :P