Heinrich Rudolf Hertz was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's equations of electromagnetism. The unit of frequency, cycle per second, was named the "hertz" in his honor.
Heinrich Hertz
Memorial of Heinrich Hertz on the campus of the Karlsruhe Institute of Technology, which translates as At this site, Heinrich Hertz discovered electromagnetic waves in the years 1885–1889.
Heinrich Hertz
Ueber die Induction in rotirenden Kugeln, 1880
Electromagnetic radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. Types of EMR include radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays, all of which are part of the electromagnetic spectrum.
James Clerk Maxwell (1831–1879)