The power output of a laser is measured by its wattage, the number of joules of energy it radiates per second (1 W = 1 st). A 75.0-mW krypton laser produces a beam of blue light with a wavelength of 476.2 nm (4.762x107m). (a) Calculate the energy carried by each photon. (b) Calculate the number of photons emitted by the laser per second. (a) 3 per photon (b) photons per second