Strategies to form n-type semiconductors include increasing the amount of metal in ZnO or TiO2, while increasing the amount of nonmetal in Cu2S, CuI, or ZnO leads to formation of p-type semiconductors. Explain why

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.