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

[UrbanXrisis]

the fomula $$\frac{h}{\lambda}$$

is this for the photon only? or can it be applied to relativistic electrons too?

 

[anjor]

it applies to particles with zero rest mass. Hence it won't apply to relativistic electrons.

 

[UrbanXrisis]

so for relativistic electrons, if I wanted it's speed, i'd use .5mv^2?

 

[dicerandom]

1/2 m v^2 only works for non-relatavistic speeds, the energy for a relatavistic particle is different. See here for more details.

 

[gulsen]

it applies to particles with zero rest mass. Hence it won't apply to relativistic electrons.

Same question was asked by de Brolie. And actually, it turned out that it will.

 

[topsquark]

Same question was asked by de Brolie. And actually, it turned out that it will.

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.

-Dan

 

[gulsen]

No, it comes from:
$$E = pc = \frac{hc}{\lambda}$$
where c's cancel, and de Broglie's equation relates momentum and wavelength.

 

[topsquark]

No, it comes from:
$$E = pc = \frac{hc}{\lambda}$$
where c's cancel, and de Broglie's equation relates momentum and wavelength.

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.

-Dan

 

[UrbanXrisis]

so $$p=\frac{h}{\lambda}$$ is for massless particles

but what about $$E=fh$$?

is this equation for massless particles too?

 

[topsquark]

so $$p=\frac{h}{\lambda}$$ is for massless particles

but what about $$E=fh$$?

is this equation for massless particles too?

No. This equation is good for anything. Basically this equation simply expresses the quantizability of energy.

-Dan

 

[gulsen]

so $$p=\frac{h}{\lambda}$$ is for massless particles

but what about $$E=fh$$?

is this equation for massless particles too?

No, it applies to all particles! That's the backbone for Schrödinger equation!