Practice question · Multiple choice
Below a certain frequency, no electrons are ejected from a metal no matter how intense the light. What does this establish?
Hints
- If energy arrived continuously, a bright enough beam would always eventually work.
- The existence of a sharp threshold means one photon must suffice on its own.
Show the answer
D. Light delivers energy in discrete photons whose energy depends on frequency
Why
A continuous wave would let a dim beam accumulate energy until ejection. A hard frequency threshold means ejection is a single-photon event, so energy must arrive in quanta of size .
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