1. Not finding help here? Sign up for a free 30min 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!

The fomula h/lambda is this for the photon only?

  1. Feb 25, 2006 #1
    the fomula [tex]\frac{h}{\lambda}[/tex]

    is this for the photon only? or can it be applied to relativistic electrons too?
  2. jcsd
  3. Feb 25, 2006 #2
    it applies to particles with zero rest mass. Hence it wont apply to relativistic electrons.
  4. Feb 26, 2006 #3
    so for relativistic electrons, if I wanted it's speed, i'd use .5mv^2?
  5. Feb 26, 2006 #4
    1/2 m v^2 only works for non-relatavistic speeds, the energy for a relatavistic particle is different. See here for more details.
  6. Feb 26, 2006 #5
    Same question was asked by de Brolie. And actually, it turned out that it will.
  7. Feb 26, 2006 #6
    Yes, but UrbanXrises' original formula was either a typo or assumed that c=1. With c=1 this formula is, in fact, only good for massless particles. DeBroglie's relationship involves the speed, which is less than c.

  8. Feb 26, 2006 #7
    No, it comes from:
    [tex]E = pc = \frac{hc}{\lambda}[/tex]
    where c's cancel, and de Broglie's equation relates momentum and wavelength.
  9. Feb 26, 2006 #8
    :redface: I was thinking of the energy equation. Sorry! (Ahem!)

    Even though I got my c's wrong, the argument still holds...E=pc only hold for massless particles, which was what I was trying to say.

    Last edited: Feb 26, 2006
  10. Feb 26, 2006 #9
    so [tex]p=\frac{h}{\lambda}[/tex] is for massless particles

    but what about [tex]E=fh[/tex]?

    is this equation for massless particles too?
  11. Feb 26, 2006 #10
    No. This equation is good for anything. Basically this equation simply expresses the quantizability of energy.

  12. Feb 27, 2006 #11
    No, it applies to all particles! That's the backbone for Schrödinger equation!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: The fomula h/lambda is this for the photon only?