What the Photoelectric Effect Is
Start with the observed event: electromagnetic radiation reaches a metal surface and electrons leave the surface.
Light can release electrons from a metal surface
When electromagnetic radiation reaches some metal surfaces, electrons can be released. This observed event is called the photoelectric effect.
Definition
2 marksWhat is meant by the photoelectric effect?
Model answer: The photoelectric effect is the emission of electrons from a metal surface when electromagnetic radiation is incident on it.
The emitted electrons are called . The definition needs the emitted electrons, the metal surface and the incident electromagnetic radiation (9702/42/M/J/25 Q9(a)).
A student writes, “The photoelectric effect is when light gives electrons more energy.” Why would this not earn both definition marks?
Show worked answer
It does not state that electrons are emitted from a metal surface, or that electromagnetic radiation is incident on the surface.