− | Visible light has wave-length between 3800 Å and 7800 Å. These wave-length correspond to frequencies from 789 up to 385 THz. So, the declaration of "full vitality" would correspond to red light and having an energy of 2 eV per photon, ultra-violet light having an energy of 3 eV per photon (1 eV = 1,6 · 10<sup>-19</sup> Joule). | + | Visible light has wave-length between 3800 Å and 7800 Å. These wave-length correspond to frequencies from 789 to 385 THz. So, the declaration of "full vitality" would correspond to red light and having an energy of 2 eV per photon, ultra-violet light having an energy of 3 eV per photon (1 eV = 1,6 · 10<sup>-19</sup> Joule). |