Author: Khan Academy via YouTube
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When light at or above a threshold frequency shines on a metal surface, electrons are emitted from the surface. This phenomenon is called the photoelectric effect. The photoelectric effect is evidence that light is quantized—light exists as discrete packets of energy called photons. The greater the frequency of the light, the greater the energy of its photons. A closely related phenomenon is the photovoltaic effect, which is the underlying mechanism of solar cells.

Sections:
00:00 – Intro
00:35 – Dependence on frequency/wavelength
03:06 – Threshold frequency/wavelength
03:54 – Dependence on intensity of light
04:56 – Failure of wave model of light
05:19 – Particle model of light (photons)
06:07 – Photon energy
07:32 – Particle nature explains photoelectric effect
08:45 – Intensity of light in particle nature
09:56 – Wave-particle duality
11:25 – Photovoltaic effect

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