that would eventually win his first and only Nobel Prize in Physics
20:06 but it would still be a while before I'm stands photon model love light
20:10 would gain widespread acceptance within academia those models show that like can
20:15 behave like a particle when being absorbed
20:17 there was no indication that like behave like a particle when being omitted
20:21 or in the intervening time between emission and absorption
20:24 one decade before Einstein published his groundbreaking analysis on the photo
20:28 electric effect
20:29 an experiment opposite to the previous one had been performed by another German
20:34 physicist
20:34 named bill Holman Road getting who produced the first X-rays
20:38 he did this by firing high-energy electrons at a piece of metal
20:42 which yielded electromagnetic radiation that was almost entirely and
20:46 x3 region of the electromagnetic
20:48 NetIQ spectrum the phenomenon was called bran stolen
20:52 according to the way picture a flight what should have happened was that when
20:55 the incident electron struck the items in the metal sheet
20:58 there should have been a shower electromagnetic radiation
21:02 every frequency this is analogous to striking the symbol
21:06 which will produce sound waves that cover an entire portion at the audio
21:09 spectrum
21:10 this is not what happened though the resulting electromagnetic waves were
21:15 X-rays
21:16 they didn't include all x-ray frequencies in fact
21:20 what did happen was the river so the photo electric effect
21:23 the greater the kinetic energy of the incoming electron
21:26 the higher the frequency and those energy up the outgoing photon
21:31 the wave theory broke down once again well with Einstein's boat on theory of
21:35 light
21:35 the results made perfect sense the frequencies are the outgoing photons
21:40 were dependent upon how much energy the electrons transferred to the atoms that
21:44 they struck
21:44 which suggest that the nature of this interaction is discrete rather than
21:48 continuous
21:49 and again this makes no sense under the weight paradigm applied
21:53 such results only make sense within the context of light acting like a particle
21:57 the equation for braums trillin is Kate
22:01 equals H times F Max where cases the kinetic energy of the incoming electron
22:06 f max is the maximum frequency of light emitted
22:09 and H as usual is Planck's constant
22:12 notice that this equation is almost identical to that of the photo electric
22:16 effect
22:17 this makes perfect sense since it's the same process just reverse
22:21 you may also notice that in the case have been struggling
22:24 there's no work function that's because the value for it is so small compared to
22:28 the energy is being dealt with that it can be neglected altogether
22:31 but in principle these equations which represent the absorption and emission of
22:36 light
22:36 are both based on the underlying principle that light behaves like a
22:39 particle
22:41 so those for its been established that light behaves like a particle when it
22:45 submitted
22:46 and behaves like a particle again when it's absorbed
22:49 what about the time in between enter arthur compton in 1922
22:54 who fired x-ray beams at Bloxham carbon and measured the wavelengths of the
22:58 outgoing electromagnetic
22:59 radiation the phenomenon that he was experimenting with is called scattering
23:03 which can basically be summarized as one thing hitting another thing
23:07 unlike the previous experiments would Compton was explicitly measuring was the
23:12 wavelengths
23:13 which again is defined as the distance between two successive peak civil wave
23:17 according to the wave picture applied when an electromagnetic waves strikes in
23:22 electron in the carbon
23:23 the electron should absorb some of the X-rays energy and start oscillating in
23:27 response
23:28 this in turn should cause the electron to re radiate that energy in a variety
23:32 of directions
23:33 in the form of scattered electromagnetic waves the key point is that the
23:37 wavelength of the light beams that come in
23:40 and the light beams they get rereading it did should stay the same
23:43 lambda denotes the wavelengths of the incoming light
23:46 lambda prime denotes the wavelengths the outgoing light
23:50 according to the wave theory of light these two value should be equal
23:54 throughout the scattering process
23:56 but they weren't after the experiment was performed