[kevinkevin]

  I am reading a very good text book this summer but I have hit one section in which it does not provide too much information about the given equations and concepts.  My first question is about the equation E=hV.  The fact that planks constant is used to calculate the energy of a photon with a given frequency (V) shows that the energy of photons is quantized because all the energies are a multiple of planks constant right?  This means that any energy that is not a factor of planks constant can't possibly be the energy of a photon correct?  Also, why does plank's hypothesis predict a fall off in the spectrum for black body radiation at high frequencies?  Is it because the atoms making up the material will not as easily except high energy photons?  Possible because atoms like being in a low energy state?  But that does not seem correct to me, there must be another reason.  Can anyone shed a little light on this for me?  Thanks! 

[Bublik]

Keep in mind that when you say "'the energies are a multiple of Planck's constant"', the energy doesn't have to be a whole number. Energy is measured in Joules, and as long as you have a positive real number (for a photon) that it is perfectly possible. So I don't see why your statement about multiples is significant.
As for your other question, I myself do not know, and I hope someone else answers it so we can both learn something. 

[kevinkevin]

  Now that I think about it, the multiples of plank's constant does not appear to be too important.  I think I was thinking too much about the idea of quantization and forgot that light can have all most any wavelength, and since it is the wavelength multiplied by planks constant all most any energy is allowed to be carried by a photon.. right?     

[Bublik]

Yes, you got it.

I saw you mentioned

all most any energy is allowed to be carried by a photon.. right?

and I did some research to find out if there is a finite limit for how much energy a photon can carry. Turns out, technically, there is.

Quoting someone else's post on a different forum: There's a practical limit, of a sort, where a photon has a high enough energy that it and a microwave background photon have enough energy in their center-of-momentum frame to create electron-positron pairs.

I'm not sure if you wanted to know that, but it never hurts to expand one's knowledge on matters 

[kevinkevin]

  Great, good to have that information, thank-you!