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If the incident light at 360nm causes photoemission of electrons, wouldn't the color be ultraviolet? I know that it isn't a visible color, but that's what my chart of the light spectrum says.

Unless I am misinterpreting it, which I might be. What's also mentioned in the question was that it has a stoping voltage, although I don't think that affects it.

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up vote 2 down vote accepted

The "color" of a photon can be ultraviolet. Visible light is just a small part of the electromagnetic spectrum. Ultraviolet is the part of the spectrum with slightly shorter wavelengths than blue and purple. Many materials have a threshold wavelength in the ultraviolet. And for any material with a threshold wavelength in the visible, ultraviolet light will cause photoemission of electrons (because ultraviolet photons have higher energy than visible photons). so it's perfectly normal to see ultraviolet light being used in photoelectric experiments.

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