Lecture Notes (Photoelectric Effect & X-Rays) - Dickey Physics

- Einstein's theory said that light energy is bundled into discrete
units now called photons; Einstein's theory worked to explain
the PE, but could not explain interference of light
- the result is two models of light whose basic ideas contradict one
another; one says light behaves like a wave; the other said it
acts like a particle
X-Rays:
- X-ray radiation was discovered in 1895 by a German physicist
named Wilhelm Röntgen
- like the PE, it too did not fit with classical physics theories
- it eventually required the idea of quanta to completely explain
their effects
- the discovery of X-rays, which were often called Röntgen rays,
had important consequences for atomic physics, medicine,
and technology
- Röntgen discovered X-rays while experimenting with cathode
ray tubes; he noticed that a screen coated with a fluorescent
material (barium platinocyanide) glowed from something
being emitted by the cathode ray tube