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Basic Physics III Lecture 11

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a goal I guess it's a big weird to start with a summary I didn't
get the summary of we elect from a medically checked the last time that just some what we did last week the rule that Maxwell's equations rich solemnly prom achievement of 19th century physics describing electric magnetic and optical phenomenon and therefore occasions application the first one is their electric charges on the sources of the electric skulls assault for the electric field that underwent medic charges the skulls Of all the magnetic field the changing remaining fields all about today with circular electric fields which is currently and finally a current changing electric fields of it was as a circular magnetic field and that is Olimpia's them consequence of and Maxwell's equations is that are there ought to be a transfer electric Grenada great which I admit it from charges of these charges are over and the propagation speed as it should be given by this equation multiplies sees you a not Epps not sure equal want and that tries propagation speed all policies off lead times 10 8 meters per 2nd which is identical to the low end of cars as always a these speed of light equals frequencies time wavelength collect magnetically if there are planes on this ordeal waves the electric field amplitude and magnetic field and food are related by the speed of light and this form of electric and magnetic fields are perpendicular to each other and because of France was waived their perpendicular to the direction of propagation there's a very large electromagnetic waves spectrum and we can define appointing rector rich the cross product of electric and magnetic field divided by not in this low point in the direction of propagation and the magnitude of the blows it give me intensity In letter the mythical electromagnetic waves also carry momentum and therefore they exert radiation pressure on anything that absorbs all reflects electable Nader graves are used extensively and human communications in the model sold now let's stop the new chapter and I I'm going to a challenge you with a little puzzles you're probably aware of that if should look at the world the mirror image has left and right switched so how come it doesn't have up-and-down switched and this is true even if you lay on the side of Tokyo had an up-and-down novels which so I'm going to tell you the answer the next lecture so if we look at a very smooth surface like this picture we discover image of the world or a reflection which seems to be fairly faithful to the original and to analyze
such questions you is the rating model flight to Seoul in spite of the previous chapter for the time being we are going to ignore the wave nature of the life and they simply define raise elected farther away meaning that lays perpendicular put away from goal his services for a circular wave and on the plane as long as a life travels in straight lines and remodeled as well so you can think of array also an extremely narrow beam of light and as an example if you look at a pencil you can imagine that pencil emits many many light rays and a small bundle them and your eyes and then you can see like any models the remodeled isn't idealization and neglect the wave nature of life however we can describe a reflection refraction fractions as well as the formation of images and lenses and did a description of his marvelous geometric so the subject is often called geometric optics if we remember from the latest chapter of the of reflection if you define an annual incidents which is the angle between the incidence rate and ran and normal aligned perpendicular to the reflecting surface then lost says that incident angle must equal reflected of consul reflective and always angle often reflected parade at the same time a normal but she is a solid looks like three-dimensional this law effectively holds only if the services moved so if you have a rough
unix solo a lot still valid however because each rate reflects different slightly different part of the sofas and therefore the normal Of those Little where pieces points in many different directions reflected race seemed to go or not bonds in all directions and that is called did it was reflection if have a smooth surface however and all the almost point in the same direction and a a bundle of race there's of all reflected at the scene and is a reflection is called Spec so what does I really needed for the Rays model smoothly into an infinite sewer since all things are made out of Athens and that would mean that arose on not possible because at some point after some other points are not and this is not a perfectly smooth surface and more however the waves Billy Wayne a movements this is correct up till the extent of about the wavelength band and that's good enough and therefore most are possible so this is just the a philosophical problem you cannot can't imagine rose to be continuous rapid distribution rather than consisting of solely have us specular reflection if the surface is smooth and diffuse reflection it's not
From now on we looked at a specular reflections and let's start with an example so let's say we have a tool slapped morose which are perpendicular to each other light shown diagram and the incoming ray of light makes an angle 15 degrees the 1st known as show on the picture and the question is what Angola will be out going being made with the 2nd and the fight against 1st need to find the incident angle of the problem incident angle of the problem of the Englewood makes with respect to the normal copy of this scheme here sketch of the normal direction this services incident angle and this Angola's 15 degrees and that means that the incident angle which is a call for you don't want him that has to be a 75 degrees to look
now it is at the bottom sketch a B B of cause and all that reflected race passed at the same time Anglesey that with respect for the normal so they don't want equal status but we can also draw triangle going from the 1st point of reflection of the 2nd fond of reflection and making a right angle in the middle and because this is a ride and the triangle that means that a faded to a favor 1st 90 degrees must be equal to 180 degrees off faded to a state of must be equal 90 and that means that their Pierce 90 degrees minus 75 degrees or 15 degrees so the incident angle for the 2nd reflection of 15 and all weekend times state of 4 for reflected out going down so that this the same as being loft reflection also 15 degrees and if you wanna find the angle it makes the sorrow that would be paid a fine and that means it is a 75 degrees and but in this case we also observed that incoming and outgoing berets apparel
let's look at light reflection In the real world so he'll and a box that makes fireflies race and I can hold of America Inc and it tilted slightly the new law will None of the moral indicating where paper but a conceded the angle of incidence equals angle section so now let's look it images from a plane Levin VOC image over and we see anything at all brain always assumes that a light travels the straight race so it doesn't take into account the reflection opened a new surface therefore even tho the object itself is sitting down here and the just get reflected our eyes by means of the what we actually see a light breeze coming from those points away bundle of race for example you from the bottom and hear from the top of the effect of the Neuron then enter the so we have the real object and be heroin an apparent image offered to let voters not real for example we cannot touch the weekend calculator but a position Of the of the image and do that you observed that this triangle of which so right triangle formed from the U.S father of the model to lead a plane off the road to the point of reflection said this triangle is congruent To allow that triangle which is the accrual inching connecting the uh the bottom of these image to other 2 points and the reason lights congruent is because these at least 2 angles incident and reflected and must be equal and to their reflected and it repeats itself here are behind them and therefore this Angola's 90 degrees minus the incident angle this angle is 90 degrees minus reflected an and so we have angle that this a equal in triangle by construction the angle and he'll be all right angles from 2 angles equal and they triangle share 1 sided with the 2 angles on 1 side and that means that these triangles are congruent and if they are congruent them the distance from later Dean purchased this the object To the room must be equal the distance from Beatriz seen riches distance from there of removed the image so image and object not at the same distance from the just on opposite sides and Miss image is that a so-called virtual image and the reason why call it virtual is that they are actually know like race in sport and those are just a imaginations construction by image no actual light troubles from year to year cars behind so that the images called a virtual images that so let's make an example let's consider a 1 . 6 meter tall woman who stands in front of a vertical airplane and the question is what is the minimum height of the and how Close mustard slow to the floor if she is to be able to see a whole body and we assume that time is up 10 centimeters below the top of head to solve this problem again geometrically deconstruct several points on that 1st of all . 8 is 1st point is top find easier the IOC efforts top part of the room he is the bottom of the ages the top of the image seized the bottom of these the pain of the road just before and also construct a point at which is at the the same height as beat this is a right angle and you observe that triangle formed by every and so this want is Congo and the triangle ambient eat on that 1 and the reason is arrested for that we had this angle he must equal to that end these 2 angles are right angles and therefore equal with each other and share 1 side so we have to angles on 1 side and means the final say congruent and if they are congruent that means that the dissidents from Plato and must be the same as distance from them to eat is the height of our eyes and its 10 centimeters below Top Of red so that's 1 . 5 meters off the floor and that means they be 0 M have to be I don't at the height of . 7 5 meters so already sold by the pound will close leader lawyer at test of each with a floor that seal on several he can now similarly define a point and means that sitting in the middle between GE and eat and repeat the same exercise and then we find that this point mn . at which is at the same time must being at 1 . 5 5 and so these minimum height of the it's 0 . 8 the difference between 1 . 5 5 meters until . 7 there's 1 that we didn't really consider what if a person with a three-dimensional object and so sold is not exactly the same distance from Earth so if she had a really long feed than actually in the bottom part of the moral has vast to be longer than shown here however as Islamists sequences just 1 plane for the object 1 distance the room formulas of course Soviet pretending to beginning
Arab picture of the chapter which shows the reflected image and the real world simultaneously and regress tumors is this photo are correct or is it actually up and down and at 1st glance you would think we can't tell so I can turn this picture around and it at 1st glance it looks to be exactly the same but then you noticed some differences of 1st of all In this case the people in the background on right side up and hear the upside down there is no equivalent and if you look at the image of the sun dishonest images key the branches the Treaty this woman not and of course this things that the picture wrote so we came out broad a sketch of the scene and find out which is actually correct orientation so you we have the branches which are between the camera and the sun otherwise we couldn't find any such a case the sun shines through the branches and so in the case of the reflected array reflected raised state he off those branches and because they are lower than the directories so it is the direct image of the sun that shines tho the branch which means riffraff Top on this is tough and picture indeed was upside down for similar reasons that people appear only on and on and on the bottom him on the top and his as discussed before with the length of a woman's feet perfect correspondence between America is object is only true if you consider just 1 plane so we have different depths different distances of the camera for the branch for the people and for the Sun viewing angle gets changed a little bit and you can manage can't tell the difference between don't run so I hair now it gets it gets more complicated every now and the morose and instead of just a plain wrong and we take out a section of fear and covered with reflective coating and then to such rose or a possible this 1 is called convex mirror this 1 is called a concave moves for the convex mirror a reflective coding is on the outside of the and for the concave mirror it is on the inside of and so error for the convex nor are we have erased from a distance most be beverage after cars than normal which of course always intersects with the center of the original sphere this changing like that and I can actually show you that in the real world go back tool to Little William ridden in Colombia final of course a
convex and do tendency that reflected a raise of going outside if I look the concave however be raised a a conduit for other than does so if we ever caught about concave numerous then that peril raise seem to be focused and into 1 point so all those all 5 race they meet and in 1 point and that point it's called the focal point is to look warily carefully to but did it is a work we actually see that this focusing isn't quite sure of the phrase doesn't
quite go got the same point as the and that is 8 a spherical aberration sole heir to draw perfect picture especially for knowledge those ways that are far away from the from the center of the room they meet in a slightly different point and the focal point as the bigger you make them where are the biggest be spherical operation and his spend and not quite so another observation we made is that objects all race have divergent bundles lightly but if they are far away then they look almost parallel and therefore suck since you know that such power will raise get focused 2 1 point and it can actually former image of a lease distant objects so to find a focal length all the distance between our focus and he again look a little bit off geometry so we have this triangle he'll miss triangle 2 angles river of the same this angle must be the same as that angle because it is constructed triangle constructed between will parallel raisins 1 online and that means that this pistons CDs and the distance there must be a must sale of a triangle that 2 angles on the same as the 2 sides also have the and that means that a triangle is formed from the center of the sphere I'm sorry forgot that part Solaris this point is is actually the center of the sphere therefore it is angle must be equal to that Mendelssohn's a line drawn from the center this year is always a normal correction physical so this angle equals that angle and this equals that angles which were angles are the same and 2 distances are all the same the distance CDs and the distance of beef and beef assumed that numerous small meaning that he is not too far away from a can approximate the systems be half the distance a year and the distance the focal length the distance between focus admiral and the distance is seen is of course the radius for the approximation that numerous small these these so distances which are equal with each other and must add up to raid we therefore get the focal length 1 Of the radio's that's an important thing to remember
for the year spherical picture radius the focal length is half of the and set out of all the location of images geometrically an can construct such images by using me title rates 1st we look at apparel over a period an object given I had a lot of half point and the top point and if you have a power will race then it gets reflective tho the focal point that's the ideal focal point the 2nd title phrase instead of making apparel Arabian array that goes from the object believed focal point and that becomes parallel Maine on 2 and then finally a a goes in the direction of the 2nd field and the object there at this that's reflected on itself and so those we raise their and Medan approximately 1 location and that is the the occasional the image of this object point he had if you look at a point at all freeways identical Her to each other and they all reflect on public charter told you just assume that the image location for the bottom them at the same distance from the let's not calculated the images rather than just constructing and with a sketch so at the same object with . org prime and . 0 and now we have to consider more triangles there's actually a also form can draw and 4th grade air goes to the center of the world and at the center of the world is as Kalimba behaves like a plenary meeting the normal just this horizontal line or the so-called optical axis and therefore this angle for the Centauri must be equal to that so now there are differences of more triangles consider this triangle between old all prime and they call between 2 objects points and pointed them at the center of the world and we also consider matter I II Prime or the 2 image points and the same point in the year and now we observe that all 3 angles are similar to this Randolph must be
equal To bat tangled because of the law of reflection and this angle it is a right angle by construction and this angle is the right angle like construction so we have to angles of the same and therefore the 3rd angle must also be said however that food finals are not congruent quite obviously different sizes just similar to each other and that means that I can that take equivalent sides and from Rasia age not just the height of the object divided by age I urge the size of image must behave like the distance from 8 to all 0 which is the object distance 8 I which purchased image we can form this racial collection now we look at another set of triangles this month that this form of the pressing coupons but not with the focal point is the 3rd 1 and that want and we find that those 2 triangles also similar 1st of all of this angle must equal to that angle because that's just straight line and this is a straight line those opposing and must be then again by construction this tangled with a right angle on this and and therefore coastal triangles also similar to can conform a civil or a shield so this side is the image height the reason why it is the image hiatus because this is a focal Ray and gets reflect apparel so this is image higher and this has to be or the equivalent a for the other triangle with this on the object ties and I can relate that ratio between object and image tied to the distance OF and the distance at 8 those likable sites for a the distance at 8 is just the focal length and OF the difference between object distance miners for forbid this ratio and this summer mathematical gymnastics can actually sold those Lee H. bowl waged by hair falls out can directly said these 0 would be to this racial and I get the so-called that lends equation which relates the inversely focal length to invest some of the image and the object more can define magnification riches they ratio image of object type that must be equal to the ratio of image distance away object and by convention insert a minus sign him because this images upside down compared the that's where we stood minus sign those 2 occasions help you understand all kinds of mirror images it is valid for concave Morales In that case the convention is that a radius and focal length considered to be bigger than 0 a convex Morales in this case the smaller than 0 as well as plain morose in which case an alarm over the and 1 of the focal length is considered to be 0 or the radius and focal length is considered to be in it is valid for real and virtual images are pride images will be a image and height and the object have the same sign and inverted images we have opposite signs it's valid for objects and images in front all Of the role behind them and if that multiple most of them can apply lends creation of Nordic creation in secret confessed consider the 1st and them at consider the 2nd so the image of the 1st becomes the the object of the 2nd finally says the ratio and it's called lateral magnification to make this equation and work for you have to pay a very careful attention to the sign the that played platelets of this equation a little bit and 1 can play Samoa and here on Monday and changed the curvature of the and for example we can Adam theme and see that How the that focused on focal point this appanage doesn't consider a collaboration so it's actually can also see what happens if these have been comes at an angle I'm in that case be erased still get concentrated into 1 point at that point is no longer on the symmetry axis called optical acts somewhat above focal distance doesn't change its just focal point gets moved up or down winner funding b Donald G. races again can put a diverging raise as well as a bundle of religion and divergens actually changes the effect of the war I can wouldn't object led their say year image-forming using me raised parallel raid the focal race and the sent a week and see what happens we will be object the way the image gets closer and closer to the focal plane and more in the opposite direction eventually the same position exactly where she's object was
to radius away from the distance between object and his wife radius and then as a forging closer the image gets further and further away becomes also bigger and bigger eventually becomes a virtual image will move on this case study just like for the virtual image on the plane may annoy all actual raise coming from image of itself it is just abstraction off of seeing the image and the full image as his senior year it is up right compared with the original object and do you have virtually images also bigger for the concave also is bigger than that object itself and as you approach focal
point image again have moved further and further away and also becomes bigger so let's just consider 1 bad example here so let's assume we have a 1 . 5 centimeter by diamond ring that displaced 20 centimeters formal concave with a radius of curvature of cities and the problem is to determine the position of image and its size is so full pot they are we 1st calculated the focal length that half of the radius of the radius of curvature stood divided by 2 gives us 15 cm for the focal length MLB was Lenza creation and a gives us relations between image distance focal length of object systems and is soulful 1 over the image distance we get 1 over the focal distance minus 1 on the object distance or 1 15 cm minus 1 with 20 and that results and image distance of 60 centimeters and since the signing of positive that means that the image appears in front of the not behind and now weekend our calculate the magnification taking the ratio image optic distance the minus sign and that gives us a magnification of my history and since these magnification is negative means that the images in multiplying factor of minus free With the 1 on 5 sending me the height of the object of the ratings gives us a minus 4 . 5 sending Soviet images actually bigger than doing itself and just out of curiosity to change this problem and instead of placing it at 60 centimeters which image distance of previous what happens that regimes are exactly the same now would take difference of I want above 15 centimeters minus 1 over 60 we get me there a hasn't image distance the Arab League distance where the object lost before so if you plays object its image than you will find an image where the object was originally and that is because light rays are reversible it is not true for the magnification in this case the magnification Toby miners along with and since the original ring was 1 . 5 centimeters the images not only . 5 cents but image and object as trade places with you will want to the position of the other so I think you're
Diwan <Möbel>
Satz <Drucktechnik>
LEAR <Physik>
Toyota Land Cruiser
Magnetische Kraft
Angeregtes Atom
Römischer Kalender
Optische Weglänge
Pfadfinder <Flugzeug>
Gelenk <Technik>
Diamant <Rakete>
Pfadfinder <Flugzeug>
Relativistische Mechanik
Absolute Datierung
Elektrische Ladung
Schnecke <Maschinenbau>
Umbra <Astronomie>
Optisches Spektrum
Kaliber <Walzwerk>
Elektromagnetische Welle
Direkte Messung
Hulk <Schiff>
Dipol <Nachrichtentechnik>
Buick Century
Fuß <Maßeinheit>
Außerirdisches Leben
Stardust <Flugzeug>
Front <Meteorologie>
Brennpunkt <Optik>
Proof <Graphische Technik>
Band <Textilien>
Source <Elektronik>
Scheinbare Helligkeit


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Titel Basic Physics III Lecture 11
Serientitel Basic Physics III
Teil 11
Anzahl der Teile 27
Autor Smy, Michael
Lizenz CC-Namensnennung - Weitergabe unter gleichen Bedingungen 3.0 Unported:
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DOI 10.5446/12947
Herausgeber University of California Irvine (UCI)
Erscheinungsjahr 2013
Sprache Englisch

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Fachgebiet Physik

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