Exam-style question
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What experimental observation supports the photon theory over the classical wave theory in explaining the photoelectric effect?.
- A.The intensity of light affects the number of emitted electrons.
- B.The speed of emitted electrons depends on the light intensity.
- C.The emission of electrons occurs only above a certain frequency.
- D.The wavelength of light determines the kinetic energy of emitted electrons.
Model answer
What a good answer should say
- The emission of electrons occurs only above a certain frequency.
Explanation
Why this works
Classical wave theory predicts that intensity (energy per unit area) should determine electron emission, but experiments show that below a threshold frequency no electrons are emitted regardless of intensity, supporting the photon model.
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