Hertz_heinrich5



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 * Hertz helped establish the [|photoelectric effect] (which was later explained by Albert Einstein) when he noticed that a charged object loses its charge more readily when illuminated by ultraviolet light.
 * 1887 he made observations of the photoelectric effect and of the production and reception of electromagnetic (EM) waves.
 * His receiver consisted of a coil with a spark gap, whereupon a spark would be seen upon detection of EM waves.
 * He observed that the maximum spark length was reduced when in the box.
 * A glass panel placed between the source of EM waves and the receiver absorbed ultraviolet radiation that assisted the electrons in jumping across the gap.
 * He observed no decrease in spark length when he substituted quartz for glass, as quartz does not absorb UV radiation.
 * He did not further pursue investigation of this effect, nor did he make any attempt at explaining how the observed phenomenon was brought about.