electromagnetic radiation with a wavelength of 745 nm appears as red light to the human eye. the energy of one photon of this light is 2.67 × 10-19 j. thus, a laser that emits 1.3 ×10-2 j of energy in a pulse of light at this wavelength produces photons in each pulse. electromagnetic radiation with a wavelength of 745 nm appears as red light to the human eye. the energy of one photon of this light is 2.67 × 10-19 j. thus, a laser that emits 1.3 ×10-2 j of energy in a pulse of light at this wavelength produces photons in each pulse. 3.6 × 1019 6.5 × 1013 4.9 ×1016 4.7 × 10-24 2.1 × 10-17