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Basic Physics III Lecture 20

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Automatisierte Medienanalyse

Erkannte Entitäten
Gold so every talked last week about polarization and
particularly we looked at Polaroid switch polarized light and just as a reminder polarization means that the France wave moves in 1 particular direction rather than motion goes goes any direction of his perpendicular propagation direction so after another example squared we started talking about a report organizational Cos reflected libraries and and in particular and we looked at affection off German life going from our air into water and became a distinguished polarizations the 1st formalization of the particularly in the 2nd vacationers parallel with the so-called aim of incidents and failed incidences of train that contains the incident rate reflected and the refractive right so I with every please polarization the 1 with the electric field vector is that is parallel to the plane of incidents this and where it is perpendicular to the plane of incidence meaning that it goes out there so if you look at these reflected so I'm told compared with the incident told tool our formulas that correspond to those cases the farmers perpendicular case and in this case we reflected over the incident and who food was given by this expression which depends on the indices of refraction and 1 heel and toe here and the coast side of b an angle of incidence and fracture and of course the angle perfectionist given on the same thing and not all are really interesting cases where these reflected parade is perpendicular will be a refracted through it and that is interesting because in that case there coast the refractive and is sign of the reflect the incident and and a sign of the refractive Angola's cosigned and that was the case signed off a 90 day police minus some angle authority call sign off but Bagwell foreign cosigned 90 degrees minus Alfonse he closed sign of was simply because of that fact of trigonometry is now look leave but I 1 of these cases apparel case a notice that if we incident angle order reflected angle is terrorists the the same as 90 degrees minus refracted angle and using sells off area note that anyone cosigned favor refractive equals and 1 signed incidents and and snarls lobsters this must be be equal to end to assigned fado refracted and that using again those hurdles to trigonometric identities tells us that is and and therefore since this equals wrapped red means this equals therefore there is an old reflected and food and all for the parallel case we have on polarized light meaning of equal at a mixture of a perpendicular case and parallel case as the incident light in the apparel disappear we are left with only the perpendicular case that means that we have 100 per cent polarization perpendicular to the plane of the incidents for that a reflected and that can be made use of photography and
we also talked about that 2 days ago years ago so a weekend eliminate or reduce intensity of reflected light by applying a polarizer the camera and for example can build form of photographic Scholl or emphasized the the ground compared with reflection from the pond that works because we can greatly reduce these light intensity from reflected light now we if you wanna know what Is this a magic angle correlation is 100 cent which is sometimes called the poll rising angle the Brewster angle where America we can look at the tangent of the incident and purchase a sign of the incident and all the cosine on incident an order signed over the incident angle over the sign of the refracted angle and then we applied at a snail's along with gives us the Justice and to always and sold in other words tangent of this polarizing and must be toolbar want to blow it we
calculated an example of what is being called rising angle for the case air and water and we find out that that's 53 . 1 degrees from the to indices of refraction 1 1 . peacefully and if we and find a refracted angle from the from cells law find that statistics a 6 . 9 degrees and indeed angles add up to 90 degrees
solar globalization has many applications and in particular 1 that is interesting on liquid crystal displays of liquid crystals out it is an organic material Richeson he'll fully solid golf allylic at room temperature and it consists out of long molecules and 10 to hammer out a random positions but not random alignments they tend to align themselves with the Arab neighbors directions and it's no use such LCD material and and sandwiched between glass plates and say the glass plates of scratches to do the preferred direction those molecules will be next the glass will align themselves with the direction of the scratches and if we had good tool glass plates of orientation all 90 degrees with respect to each other before kind of missed structure In the latest looks lined with Heriberto vertically scratched vast here and the molecules tend to align themselves are closed those scratches and air horizontal scratches here and that means molecules were aligned themselves horizontally here and in between area will align themselves to the neighborhoods so we gentle rotational vertical horizontal we have such a twisted structure that it is kind of like a twisted Paul Aurora to their Polaroid's will also long molecules and every month the poll let's 1 polarization tho because the other polarization does work on the charges in the molecule and that is easy going along the molecule but not easygoing perpendicular so basically a hair kind of like a whole bunch of arises now put an explicit polarized on either side BXC is aligned with those of scratches them light will get fooled because we a polarization of the which was originally vertical will be rotated by this twisted structure its horizontal goes for the horizontal followers of time so as long as we leave this structure at all and I lied will be able to pass fool the LCD but if the electric voltage that those molecules which has a rich charges on and all rich we'll get it was charges from such as they will our rather aligned themselves 2 and a even the scratches on the glass and therefore we destroy ghost twisted structures and that means that the polarization of the light going goal is normal tape and therefore we have show Gross polarized Lewis and a LCD becomes down so they said in each scene a boat LCD displays is
that they had very little power pass on Lewis who applied voltage destroys the structure and it's kind of like just charging a capacitor discharge in barrier requires very little power and yet you can turn that into displays for example pocket come so that such simple LTV's use settlements where liquid crystals and those segments or the newest displayed for or more sophisticated Aral Sea these Pixar largest term for example is little image around with cylindrical hat and such pixel ourselves is used in flat-screen TV's and where usually illuminated by from the back either by Ali diesel tourists to and it can get color and such it some those are basically just black-and-white picture can get Carlo by dividing each pixel into force sup pixel and supply them with colorful of red green and blue and by the way both the LED only LCD TV sets both share of LCD there Ali LCD just before type of illumination marked with the basic technology solar
another aspect of our or polarization Reyes look a Rayleigh scattering of light and so if if light passes the atmosphere it impinges on the Mall air molecules and and jingles the charges those molecules and and an often molecules a wee bit the light but in different in a different direction that called a light scatter and the reason why the we admit is because these are the charges legal wronged therefore we have accelerating charges and layoff the origin of dipole electromagnetic field so just like a Montana so if we had the solo right radio and hits some oxygen nitrogen molecules then at Istanbul Molly close oriented in the right way it can be a a vertically oriented horizontally oriented where it will start oscillating and will eventually of photons however because under 10 dipole antenna as don't the directional oscillation if it is a vertical molecule there will not be able to lower to removed a photon going down well if it's oriented horizontally it can In light of this going on and therefore we get a polarization effect the maximal at right angles if you look at the solar array with respect to the scattered photon still at a at right angles the only get 1 of the 2 possible polarization and some observers as sitting down sitting down on the surface of the earth this is seeing seeing poorest life and that it is a useful tool of animals for example it is 8 in and navigational beads time and on Laos and you can laugh
together similarly Lula by yeah rearing all Aurora dire sunglasses if you have them on a sunny day had invited Gordon and find the dog brand across the sky and the advantages even this summer's obscured by clouds and still find positional sun but another interesting thing of all really scared that it is proportional to bursts forth Powell the wave and that is fool as long as the U.S. scattering molecule is the size of a much smaller than the labeling of life and that means that a blue light is already scatter the and red light would be and as a consequence of the sky looks brutal us the the color of the sky is nothing else but the photons on the Sun which are predominantly blue and if you look at the sun itself its high in the sky area overseas white because it's bright and also the among the atmosphere of the sound was not much but at sunset and this August parts sunlight is passing through a lot of them have most of the dual photon task Out of the way and what is left is rare therefore sunsets then that finally the color of Childs's White told gray and the reason for that is that the scattering and this is done by a much larger regions for example water droplets or crystals those are much bigger than the wavelength all of these the light and there's no way they and in fact a mound of light scattering is independent of we're still I let me try and them on straight to lawful light scattering using them a little bit of milk mixed and Waldo so
I have leader Charles Waddell I'm tired of looking at light that's our goes out the top of the new now put a little bit of a scattering agents in them say to them and not quite enough look this is just a actually scream of chief and that I'm trying to increase scattering under a wad of of of flight that could see the color change off the France life if you look at it you always see that it's turning a little bit orange a little bit more of them slow starts to look like a son says we turned off the lights come from is misleading we definitely see the as a color of the light that is going full was changed Orange more from them do Choi shift what is not as easy easy to see it this issue will get a job from the side that looks a little bit ghoulish unfortunately we always had projected doesn't have to any moved 4 pounds in there to begin with and therefore that is a fairly famed effect looks like just the type of slight hint of a bluish light if you look at it from the sun on and so that we
some RISC read a chapter bulb the diffraction and a polarization sorry your
soul are 1st of all I liked diffraction means that light waves and around obstacles and it produces a diffraction pattern of constructive destructive interference we saw the diffraction pattern often narrow single slip of would be embezzled a bright white as essential maximum and minimum if sign the angle under which it is equals an integral number times the wavelength divided by diameter and that this tool for an integral number plus minus 1 to 3 but not 0 dead the wave nature of the light and limits was emotions but you can't obtained optical instruments the so-called really criteria tells us but the diffraction Embudo a circular aperture limits the resolution and the criteria is that if you have different objects than in the 1st minute of the area disk the circular diffraction have on the 1st point overlaps B a central maximum of the 2nd point then add those 2 points are at the limit of being able to be resolved and that 1st minimum for circular for the circular case it is for us sign favor equals 1 . 2 2 times Lon D and usually fatal small so can approximate signed and as a consequence we owe observed that allowed just youthful a light microscope magnification about 600 time if magnify Arab beyond that all receives a scratch pad rather than be object so if we combine them many different slits all reflective lines reproducibly fraction grading and they produce sharp and bright Maxima assigned a equals an integral number times slammed all of these airlines space indeed where at this time and can be 0 plus minus 1 plus 1 tool honestly and so on and and such the diffraction gratings Our used in spectrometry to separated in matters of different wavelengths for example a emission lines X-rays Our electromagnetic waves with a short wavelengths produced by collisions of high-voltage accelerator the grass of metal targets and they're useful out their diffraction is useful to study crystal structure such as a double helix of the DNA molecule and finally got polarized light means that the electric electric field oscillator of transfers directions while playing poorest light means that electric field ocellated said 1 plane only and on polarized light passing pool Polaroid sheet becomes polarized and to pull when the 1st bomb actors rise of turned the light and his life and the 2nd 1 is the analyzer and should to taxis of the 2 Polaroid sheets by an angle theta a intensity passing is proportional to lead a recall square of the and reflected light from a a similar into an optical evidence of you becomes polarized and has 100 % polarization of so-called Brewster angle which is a vote for that polarizing will boost angle the tandem of the angle is equal to and tool and Wan so list concludes
classical physics portion of its course so all what we learned to up to this point is what people knew in the 19th century and that time man most physicists believe that there's nothing more To be discovered and the only thing you can do is the measure things more precise and find you a little bit so I basically Newtonian mechanics and Maxwell's equations described the entire world and all phenomenon can be thus explained unfortunately had the wrong and the best was yet to come and the tool for revolutions that took place 1 most of these Force special volatility and eventually general relativity which modified a Newtonian mechanics and in 1 direction and the other 1 Morocco what's our quantum field which modifies both Maxwell's equations and new tone can and a quantum theory made possible a three-dimensional Ehrlich from schools and this is a bar From microscope picture and infect those little green bastards on the geology of a teary if they it assurance that a small intestine and if you ever went hiking and encounter some of these Norwood and talk
so at the time at even in the 19th century euro few puzzles live remained which kind of difficult to explain with Maxwell's equate him and Newtonian mechanics but that people just thought didn't try hard enough and 1 of those ups the little problems or a black body radiation so physicists talk about the black body it doesn't mean it's there is very black just means it is a system that it's able to absorb all radiation that so that for example can be a pinhole any radiation that goes in there and his but it can also be for example a stock like the sun because remember you by look we have radiation hitting the sun doesn't come out some just shines but it's a radiance independently of what radiation solar that bodies that have a finite temperature the defined meaning that temperature bigger than 0 making error radiation spectrum that also and that spectrum depends only on the temperature of the black and here are some examples a blackbody spectrum for over 2 thousand degrees Kelvin for cars and 500 degrees and 6 thousand degrees Kelvin and I'm planting near the frequency at the top of the electron waves and wavelength the bomb but can also will be just 1 that and right now I'm at a temperature of about 4 thousand 800 held in the heart of the naked cooler and start something like the environment as a woman little sold mold temperature flattery blackbody radiation peaks federer over a relatively long wavelength so something like 10 microns and that is that radiation score infrared radiation on a treaty which we know that make it a little bit this will haunt him for example like a Nice he then that we see that wavelength become shorter and also the amount of radiation becomes far larger so how did she go to higher temperatures city about 1 thousand degrees by the lights starts and that the radiation staff who gold wander food the visible spectrum therefore if you keep for example of steel or Byron and that stance turned red recorded red-hot as legal tool higher temperatures in radiation becomes far more intensively wavelength become shoulder and multiple wavelength of the visible spectrum participate and the object starts to appeal white white Hodges is harder than red-hot you can also see approximate their color of radiation thereby this little stormed back tool the 1 thousand the new seeds were read this son got going to higher and higher temperature starts turning white when we hit the operating temperature a typical like the honor to see that even know whole about lots of visible light to could lots more of and that's why is light all this is inefficient most of the radiation produces goes leading pop from life if it increase the temperature further suddenly eventually reach the radiation temperature of the sun this led by the way is not be the core temperature of the sun
which is not part of that just before the speed at which actually reads life and notice that lead is still a light spectrum peaks said about half of Micron in a clean each and temperature that it corresponds to about 6 thousand Calvin on this case he 5 thousand 745 and if they go to even higher temperatures than via radiation that starts to look good the rule at and that would be the case for war hottest on son not 1 thing that's a classical physics will remain where is year the peak of With respect promise of functional the temperature and given by so-called that means and that means last states that if you look at the peak wavelength times the absolute temperature the product of the 2 was constant and constant us 2 . 9 times 10 to the minus 20 meters times code bullets molded an
example example for a list of the sun's surface temperature so let's estimated his son surface temperature given that we know that the solar spectrum peaks at about 500 none of needles and we divide this as a Byzantine constant 2 . 9 times 10 to the minus 3 meters terms Kelwin by half a micron get the radiation temperature 5 thousand 800 tell
sewer but Tri-Star understand classically white black bodies and radio where you imagine that must come from applying Maxwell's equations to these molecules that make up the which for example can be the surface of when or where it can be son or whatever however 1 try to be quantitative for example the rain-delayed genes classical when you see that spectrum of predicts this just keeps that keeps rising for us to go higher frequency and that's rather bad for many reasons 1 particularly on that is to integrate the total amount of energy to come up with Infinity that's clear ridiculous and the next there's also a by being the fellow with Irvine law and that looks much better said at least gives us a finite amount of Ferreira radiation and G however unfortunately it disagrees with the experiment at and finally after almost suffering a nervous breakdowns legend has marks Plunkett this formula which are correctly describes the black body radiation however he cheated because he only energies multiples h times the speed of light divided by land and you can call that the energy and solar energy ought to be continuous so this is really an incorrect assumption however it it seems still phenomenal optically correct described so our
so what does it mean so it's as if we assume the molecules are like answers on springs their Muharram a simple harmonic motion and all energies and all and Pluto was ought to be a lot of go the potential energy as a functional position it looks like around sold anything on the blue line some of our volume for the year for the energy however plant assume that only energies which is for vertically on those red lights on and cancel a number so this is the ground level and this is 1 times each time a round sealed and so on and his or original plan and the right source he assumes that energy must be multiples of quantum but then he wanted to let those little constant H. wanted it related to a goat was 0 and then recover continues and unfortunately there if he uses a finite value for this Leonard fits the experiment however stillness to let aged goat doesn't fit experiments more and that that was What a puzzle so it seems to
imply that indeed only his only sister energy levels of all day classically all energies a ought to be possible for the inclined plane this case for potential inventory for America the a plants hypothesis it's sort of like a staircase with each step there's a each times fortunately Jakarta Missouri small even for optical frequency is on the order of 10 of the 14 1 energy quantum only on your of 10 to the minus 19 Jules so 1 could certainly on that might have escaped observations so far apparently this comes a little steps like however a nobody really talk peace call on the serious not even found himself and Everybody just for Roberts kind of Maastricht of obtained the right spectrum and someday we could do it properly and I don't think the stricken what he only 1 hole actually that took it
seriously With this fellow Croat so Einstein looked at this and he proposed a new life this new with of light as a particle fuel so this was well bearing after 100 years of success of the wave your life he suggested the prodigal and his argument is not only explains the black body radiation and it can also explain a mother which is called photoelectric in this photoelectric effect if you shine a light on medals they surface most obstinate you can construct a so-called photocell where you applied voltage tool total medals so you have an older cattle and then evacuated sold that electrons have an easier time propagating and when you shine a light on that observe current and that current varies with a potential that you I push push so for the photoelectric
effect the Ellet trance kinetic energy and thereby this speed it can be measured by stopping them an electric potential so when voltages just write that Fidelity chums don't propagate anymore on the current therefore become 0 then be a maximum of kinetic energy of electrons must be equal to the Alex charge finds the applied voltage so now we can look at it Our predictions of the wave of the based COE tells us that light intensity is proportional to the square of the electric field and that means if we have a lot of light intensity of a stronger electric field and if you have a strong electric fields at the polls most bulls more strongly on electrons and therefore the electrons kinetic energy must increase and of course it will start ripping or more the frequency of light irrelevant and true sold and of global picture of
this so he'll be hair these Ellerbe electrons Ball State of some potential imagery there in their free stayed there a higher potential due the potential difference we call our problem your parents a mode of times the numerator their energy depends on electric field and which can be controlled by the intensity of in particular the electric field this large enough that it can or will come this potential boundary from stop otherwise on it for the full-time steely however are barely hit the charms the little particles called for ponds and those photons ever particularly energy each times at like punks hypothesis and they as the big enough will kick those Eilat from strongly enough lift them up potential so I have in other words the energy intensity just controls harmony Ellett France Our appearing but not whether they appeal and also with the kinetic energy that is controlled by the frequency so all our
soul Einstein's theory of might predicts that these kinetic energy stocks of Zedillo at some frequency if not other F not as given by the condition Dublin not equal speech patterns and not a continuously rises with the frequency and luck again larger light intensity just means more photons and therefore more admitted Allah times larger overcame acts and of course the age at the small of MW zeroed in on me so the big question is was
right Einstein for all of physics before Einstein and the ads obvious of course I'd stand as tends to be here is almost always so Milliken um ever the photoelectric effect in 1930 in 1914 and there were in agreement with the photon theory and that was the 1st of our quantum mechanics and Einstein received Noble Prize with that the printed
Schaft <Waffe>
Radioaktiver Zerfall
Satz <Drucktechnik>
Patrone <Munition>
Blende <Optik>
Hydraulischer Aufzug
Angeregtes Atom
Elektrische Spannung
Puma <Panzer>
Anzeige <Technik>
Flacher Bildschirm
Negativer Widerstand
Schwarzes Loch
Zylinder <Maschinenbau>
Zelle <Mikroelektronik>
Zelle <Mikroelektronik>
Blende <Kleidung>
Gedeckter Güterwagen
Dreidimensionale Integration
Elektromagnetische Welle
Öffentliches Verkehrsmittel
Direkte Messung
Interstellares Gas
Photographische Platte
Mitsubishi Colt
Flacher Bildschirm
Elektrische Leistung
Band <Textilien>
Source <Elektronik>
Maske <Halbleitertechnologie>
Anzeige <Technik>
Erwärmung <Meteorologie>
Optisches Spektrum
Burst <Nachrichtentechnik>
Römischer Kalender
Wellenreiter <Aerodynamik>
Flüssiger Brennstoff
Magic <Funkaufklärung>
Oignon <Uhr>
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Kaliber <Walzwerk>
Experiment innen
Ahle <Werkzeug>
Walken <Textilveredelung>
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Buick Century
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Ton <Akustik>
IPAD <Kernspektroskopie>
Proof <Graphische Technik>
Source <Elektronik>
Masse <Physik>


Formale Metadaten

Titel Basic Physics III Lecture 20
Serientitel Basic Physics III
Teil 20
Anzahl der Teile 27
Autor Smy, Michael
Lizenz CC-Namensnennung - Weitergabe unter gleichen Bedingungen 3.0 Unported:
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DOI 10.5446/12956
Herausgeber University of California Irvine (UCI)
Erscheinungsjahr 2013
Sprache Englisch

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Fachgebiet Physik

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