Chemistry / Unit 5 Chem 0780 short lesson, about 20 seconds
The Photoelectric Effect
Captions available
The idea
The photoelectric effect is the ejection of electrons from a metal surface by light, occurring only above a threshold frequency, regardless of brightness.
In practice
Dim violet light ejects electrons from a metal, while bright red light below that metal's threshold frequency ejects none.
Where people slip
Increasing brightness raises how many electrons are ejected above threshold — it never substitutes for reaching that threshold frequency.
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