1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Speed of electric spark, arc and conductive ionized gas

  1. Jun 15, 2012 #1
    Dear colleagues,

    If an arc or a spark travelling in vacuum is actually the electrons jumping across vacuum, do they travel at near light speed?

    From another point of view, devices like thyratrons use ionized gas molecules to conduct electricity, at what speed are those ionized molecules travelling? Do the molecules need to travel at all?


  2. jcsd
  3. Jun 15, 2012 #2
    As you suspect, sparks consist of charged particles...often electrons, as in vacuum tubes, but any charged particles will do....as in ionized gases....even ionized air! They do NOT move anywhere near as fast as light which is electomagnetic radiation....maybe a few percent the speed of light. The actual speed of the charged particles depends on the design of the device, such as the separation distance of the charged plates and the potetial difference between charged plates.

    I do not know typical speeds in vacuum tubes, but everyday lightning bolts [flashes] move at well over 100,000 miles per hour.
  4. Jun 15, 2012 #3
    Thanks, for ionized gas I guess it is only the charge being transfered between molecules, and it is not necessary at all for the molecules to move from one plate to another. As for vacuum, I don't understand what slows the electrons down, I suppose a current flows through a wire at near the speed of light.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook