I have a few pretty simple questions that I can't seem to find a clear answer to on the net... The energy of a light wave is directly proportionate to frequency and inversely proportionate to wavelength. This is due to the energy of a Photon being equal to hf. "f" is a constant, so the greater the frequency, the greater the energy. I get that. The intensity of a light wave is based on the wave's amplitude. Why? My immediate intuitive response when looking at a wave diagram would be that there are more photons per waveform. The more photons that are hitting our eyes in a given timespan, the brighter the light would seem. Or... It would seem that the amplitude could have an effect because the photons in a wave at X frequency would have to travel faster in a wave with greater amplitude to travel the same distance forward, therefore have a greater kinetic energy. I know that light travels at C, but does that apply to the individual photons as well? Which is correct? Are there more photons, or do they travel faster? Or is it neither? Also: Why does the frequency of a wave have an effect on the energy level of the individual photons? What am I missing? Last question... What determines the amplitude of a wave? Thanks for any input you might have. I don't mind reading all this from articles myself if you don't want to go through all of it, but, like I said, I can't find the answers, so a link to a good source would be just fine, too.