What properties of waves caused the photoelectric effect to indicate the fact that light was quantized. Why couldn't it be explained by light waves being emitted at the same frequency. Im a little confused about why light couldn't still be a wave. Couldn't the photoelectric effect be explained because many light waves of the same frequency and thus the same energy be responsible for the fact that electrons only get exited by light of a certain energy. I just don't understand what quantization has to do with it.