Question: how many moles in a photon?
Answer: where E is the energy in a mole of photons, N is Avogadro's number (6.02 x 1023 photons per mole), h is Planck's constant (1.58 x 10-34 cal/s), c is the velocity of light (3 x 1017 nm/s), and l is the wavelength of light (nm).