Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Current = I = nqAv

  1. Jan 11, 2005 #1
    Current = I = nqAv, HELP

    I found this formula for current, I, know A is area, but I dont know what nq and v are... Can anyone help me?
    Last edited: Jan 11, 2005
  2. jcsd
  3. Jan 11, 2005 #2
    v=speed of electron
    n= number of FREE electron per unit volume
    q= charge of electron
    A= cross section area
    Last edited: Jan 12, 2005
  4. Jan 12, 2005 #3
    oohhhhh ok, q is a constant, makes sense... Thanks alot. V varies with the material its flowing through? And how do u calculate n??
    Last edited: Jan 12, 2005
  5. Jan 12, 2005 #4
    You can try to find out the density of lattice ions, and multiply this by the number of conduction electrons they supply. In case of a solid you could look up the lattice spacing and how many atoms are in it. Or you could use the mass density and their molar masses.
  6. Jan 12, 2005 #5
    what grade r u in? this should be easy if you have taken some very basic chemistry course....look up the density of the meterial, also the mass of atom......you can easily find out the number of atom per unit volume from the information above.... then multiply by the number of free electron per atom...
  7. Jan 12, 2005 #6
    ok, thanks for the help. I had forgotten what was meant by free. But i got it now, thanks
  8. Jan 12, 2005 #7
    v is the drift velocity of the electron.i.e the velocity acquired by the electron due to thermal energy.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook