Ultraviolet radiation is also a type of electromagnetic radiation.
In 1801, the German scientist Johann Wilhelm Ritter wanted to find out whether the region of the sunlight spectrum beyond the violet part had the lowest temperature (opposite to what Herschel had discovered). Ritter did not observe what he expected to find; however, he found out that silver chloride turned black from white quicker when it was placed in the region beyond the violet part of the spectrum.
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Here is a portrait of Johann Wilhelm Ritter:
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