Final answer:
The photoelectric effect is not explained by the wave theory of light because of the immediate ejection of electrons upon light incidence (absence of lag time), the kinectic energy of electrons depending on light frequency rather than intensity, and the existence of a cut-off frequency below which no electron ejection occurs.
Step-by-step explanation:
The content loaded with key aspects of the photoelectric effect reveals that there are 3 things observed which are not explained by the wave theory of light:
- The absence of a lag time between the light shining on a metal surface and the ejection of electrons suggests that the effect is instantaneous, which contradicts the wave theory that predicts a gradual energy accumulation before electron ejection.
- The kinetic energy of photoelectrons does not depend on the intensity of light but instead on its frequency, in defiance of wave theory which associates energy with wave intensity (amplitude).
- The presence of a cut-off frequency below which no electrons are ejected, irrespective of light intensity, which again is at odds with wave theory that does not predict such a threshold limitation.
Albert Einstein explained these observations by proposing that light is composed of quantized particles called photons, each carrying energy proportional to its frequency, which successfully explains the photoelectric effect.