A0.45 um thick sample of gaas is illuminated by a monochromatic light of photon energy 3 ev. the incident power on the sample is 15 mw/cm2. if the absorption coefficient is 50 000/cm, determine (a) the total energy absorbed by the sample per second, (b) the rate of excess thermal energy given up by the electrons to the lattice before recombination, and (c) the number of photons given off from recombination. assume perfect quantum efficiency. the outgoing radiation is of 2.35 ev.