Final answer:
The photoelectric effect is a process in which electrons are ejected from metals when certain wavelengths of light shine on them.
Step-by-step explanation:
The photoelectric effect is a process in which electrons are ejected from metals when certain wavelengths of light shine on them. This phenomenon occurs when a metal surface is exposed to a monochromatic electromagnetic wave of sufficiently short wavelength or above a threshold frequency. The incident radiation is absorbed by the metal surface, causing the emission of photoelectrons.