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

- barium platinocyanide was know to glow when exposed to UV
radiation, but no UV light was coming from the cathode ray
tube; Röntgen hypothesized that some new form of radiation
was affecting the screen
- he named them X-rays since they were of an unknown nature
- experiments performed by Röntgen showed that X-rays
originated from the glass wall of the cathode ray tube, they
traveled in straight lines, darkened photographic plates,
penetrated various substances and were not deflected my
magnetic fields
- J.J. Thompson discovered that upon passing through a gas, X-
rays electrify (ionize) the gas
- there was some debate as to whether X-rays were particles or
waves; because they were not effected by magnetic fields,
they were thought to be either neutral particles or EM waves
- if they were EM waves, scientists knew that they would have to
have a very short wavelength