The earliest photographic
The earliest photographic evidence of their existence currently dates to 1890 rather than 1895 as sometimes believed. With wavelengths ranging from 10 nanometers down to 1 picometer, they overlap with the short end of the ultraviolet portion of the electromagnetic spectrum. For 10 points—name this form of radiation discovered by Roentgen (RENT-gin).
The earliest photographic evidence of their existence currently dates to 1890 rather than 1895 as sometimes believed.
{x-ray}s [accept equivalents]