Not to confuse you, but I just wanted to touch on the fact that sometimes it is convenient to think of radiation in terms of particles or discrete packets of energy or Òphotons.Ó  When doing this remember the relation, photons with shorter wavelengths have more energy.  That is why, in spite of the fact that the sun emits more visible photons than UV photons, the UV photons have much more energy than visible photons and are thus more dangerous to humans than visible photons.  Although visible photons can harm a person in large doses, i.e. looking directly at the bright light.