2013 AD., Germany, 125th anniversary of the discovery of electromagnetic radiation by Heinrich Hertz commemorative, Karlsruhe mint, 10 Euro, KM ?

Germany, Federal Republic, 125th anniversary of the discovery of electromagnetic radiation by Heinrich Hertz commemorative, engraver: Othmar Kukula, Karlsruhe mint ("G"), 2013 AD., issue date: 21 November 2013,
10 Euro (32,5 mm / 14,05 g), copper-nickel (CuNi25), 14,00 g theor. mint weight, mintage 1.270.500 , medal alignment ↑↑, plain, incuse lettered edge,
Obv.: BUNDESREPUBLIK DEUTSCHLAND 2013 / G / 10 EURO, date and value below German national emblem eagle, 12 stars of Europe flanking, mint mark "G" in right field below wing.
Rev.: 125 JAHRE STRAHLEN ELEKTRISCHER KRAFT / Hz / {Ok} / HEINRICH HERZ , depiction of the discovery of the electric power radiation on a sphere gap (Hertz dipole) with field lines, Hertz signature (in script) and engraver´s initials in {Ok} -monogram below.
Edge: plain with incuse inscription "LICHT IST EINE ELEKTRISCHE ERSCHEINUNG •" (translation: "LIGHT IS AN ELECTRICAL PHENOMENON").
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Year / Mint Mark / Mintage
2013 / G / 1.270.500 (or 1.100.000 ?)
(plus a similar proof issue, 200.000 pieces made of 16 g. 0.625 silver)

German coins of the later Federal Republic are produced at five different mints, coins from each of them can be identified by their mintmarks, A = Berlin, D = Munich, F = Stuttgart, G = Karlsruhe, J = Hamburg.

Heinrich Rudolf Hertz (1857 – 1 January 1894) was a German physicist who clarified and expanded James Clerk Maxwell's electromagnetic theory of light, which was first demonstrated by David Edward Hughes using non-rigorous trial and error procedures. Hertz is distinguished from Maxwell and Hughes because he was the first to conclusively prove the existence of electromagnetic waves by engineering instruments to transmit and receive radio pulses using experimental procedures that ruled out all other known wireless phenomena. The scientific unit of frequency – cycles per second – was named the "hertz" in his honor.