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Named after the German physicist Philipp Lenard, who first described them.
Etymology from Wiktionary, CC BY-SA 4.0.
Lenard ray
Today it means: One of the rays that emanate from the outer surface of a plate composed of any material permeable by cathode rays, such as aluminium, which forms a portion of a wall of a vacuum tube, or which is mounted within the tube and exposed to radiation from the cathode. Full definition →