Calculate the average power output (in watts) of a photodetector that collects 8.0 x 107 photons in 3.8 ms from monochromatic light of wavelength (a) 470 nm, the wavelength produced by some commercially available light-emitting diodes (led), and (b) 780 nm, a wavelength produced by lasers that are commonly used in compact disc (cd) players. hint: the total energy emitted by a source or collected by a detector in a given interval is its power multiplied by the time interval of interest (1 j = 1 w s).