Johann Wilhelm Ritter, a German physicist, discovered ultraviolet (UV) radiation in February 1801. This discovery was made in Jena, Germany. Although it was not as widely recognized as his work on galvanism, this discovery significantly contributed to our understanding of the electromagnetic spectrum.
Ritter conducted experiments to investigate the existence of energy beyond the violet end of the visible spectrum. He observed that the light beyond the violet end of the spectrum caused chemical reactions, such as the darkening of silver chloride. This observation led him to conclude that there was a type of invisible radiation present. He named this radiation "invisible light" and later, "ultraviolet rays" because it was located beyond the violet end of the visible spectrum.
