German physicist who was the first to produce radio waves artificially. A unit of frequency equal to one cycle per second. See table at measurement. hertz Hz a unit for measuring the frequency of sound waves
German physicist who with James Franck proved the existence of the stationary energy states postulated by Bohr (1887-1975) German physicist who was the first to produce electromagnetic waves artificially (1857-1894) the unit of frequency; one Hertz has a periodic interval of one second