system
Given the following post, respond as if you're commenting on Reddit:
human
Why does light need to consist of particles to explain the photo effect?
gpt
One key to seeing this is that even as you increase the intensity of the light beam, the ejected electrons don't move any faster.  This is explicable if the greater intensity arises from having more photons.

In addition, if the frequency of the light is too low, regardless of how bright the beam is, electrons will not be ejected.  Why?  Each individual photon of this light does not have enough energy to eject an electron.