Hertz’s photoelectric effect
Stories from Physics for 11-14 14-16 16-19
Heinrich Hertz made perhaps the earliest recorded observation of the photoelectric effect in 1887, during his experiments on radio waves. Hertz had set up a receiver for radio waves consisting of a spark gap in a curved piece of brass capped with small metal spheres. Current induced by radio waves in the u-shaped conductor would produce a spark between the spheres. Hertz observed that when he placed a piece of glass in front of the loop, the size of the spark decreased. And when he replaced the glass with a quartz plate, which allows ultraviolet light to pass through, the spark returned to its original size. Hertz was mystified by the results commenting:
…the effect is striking and yet totally puzzling. Naturally it would be nicer if it were less puzzling; however, there is some hope that, when this puzzle is solved, more new facts will be clarified than if it were easy to solve.