Ans: The photon is all familiar with elementary particles. Each photon travels with a speed of light, i.e., 3 x 108 m/s, which makes them greatly significant in quantum physics, along with electricity generation.Like in the photoelectric effect, the energy of photons is transmitted through the given material, which helps in the photoemission. Thus, photoemission is the process of electrons coming out of the metal, these electrons are used in electricity generation.