History And Formation Of Newtons Rings

History And Formation Of Newtons Rings In this experiment the physical property of interference of light will be used to determine the wavelength,, of a light source. The interference fringe system here is a pattern of concentric circles, the diameter of which you will measure with a travelling microscope (which has a Vernier scale). If a clean convex lens is placed on a clean glass slide (optically flat) and viewed in monochromatic light, a series of rings may be seen around the point of contact between the lens and the slide. These rings are known as Newtons rings and they arise from the interference of light reflected from the glass surfaces at the air film between the lens and the slide. The experimental set-up is shown in figure 1. History of history of Newtons ring The phenomenon of Newtons rings, named after sir Isaac Newton who first studied them in 1717, Newtons rings is a pattern of interference caused by two surfaces after reflection of light a sphere surface and an adjacent flat surface. When view with monochromatic light its appears as a series of concentric, alternating bright and dark rings centered at the point of contact between the two surfaces. When we see with white light, it forms like a rainbow colours concentric ring pattern because the different wavelengths of light interfere at different thickness of the layer between the surfaces. The light reflected from both surfaces caused by constructive interference, while the dark rings are caused by destructive. Perhaps, the outer rings are more closely spaced than the inner. So the above phenomenon was first described by Robert Hooke in his 1664 book Micrographia although its name derives from the physicist sir Isaac Newton, who was the first to analyze it. Newtons rings The term Newtons rings is a ring formed by the glass of curved, typically a convex lens, is put in contact with a glass of a plan surface. The curved glass kept on the plan glass, forming a film of air between them is increasingly larger along the length of the curve. When light is directed into the curved glass, a many of concentric circles appears. That is why the rings are referred to as Newtons rings. Which was the first to observe the phenomenon by Sir Isaac Newton? The Newtons rings formed will be phenomenon typically is dark alternating with bright, with the dark beginning in the center. It is formed as a result of interference between the light reflected by the two surfaces. Towards the application, Newtons rings can be used by lens makers to find out the quality of a lens. In a well-made lens, the rings should be uniform. When a convex surface with its Plano-convex lens is placed on a glass sheet, an air film of gradually increasing thickness outward is formed between the lens and the sheet. The thickness of film at the point of contact is zero. If light is allowed to fall on the lens, and the film is viewed in reflected light, alternate bright and dark concentric rings are seen around the point of contact. (Source google.com) Newtons Rings, it is visible a pattern of light and dark circles when a convex lens is placed, curved side down, on top of a flat piece of glass. The pattern was first observed by Sir Isaac Newton. The rings are caused by interference of light waves. When a light is falls downward onto the two pieces of glass, two overlapping beams of light are formed-one from light reflected by the lower surface of the curved glass and the other from light reflected by the upper surface of the flat glass. The light reflected from the plane glass moves farther than the light reflected from the curved glass. It depends on the distance between the two surfaces, light waves in the two beams may be in phase, and reinforcing each other or they may be out of phase, canceling each other out. Since the distances between the two reflecting surfaces increases with distance from the point where the lens and flat glass make contact, the areas where the waves are in phase and out of phase occur in concentric bands around the center of the lens. If the beam of light falls at the two pieces of glass is of a single wavelength i.e. monochromatic, the rings are thin circles of a single color. The rings are fewer in number, but highly colored when white light is used Formation of Newtons Rings Newtons rings are formed as a result of interference between the light waves reflected from the top and bottom surfaces of the air film formed between the lens and glass sheet. The phenomenon of the formation of Newtons ring can be explained on the basis of wave theory of light i.e.: An air film of varying thickness is formed between lens and the glass sheet. When a ray is incident on the surface of the lens, it is reflected as well as refracted. When the refracted ray strikes the glass sheet, it undergoes a phase change of 180 on the reflection. Interference occurs between two waves which interfere constructively if path differences between them is (m+1/2) 1 and destructively if path difference between them is ml producing alternate bright and dark rings. Radius of Newtons Ring Let the radius of curvature of the convex lens is R and the radius of ring is r. Consider light of wave length l falls on the lens. After refraction and reflection two rays 1 and 2 are obtained. These rays interfere each other producing alternate bright and dark rings. At the point of contact the thickness of air film is zero and the path difference is also zero and as a 180O path difference occurs, so they cancel each other and a dark ring is obtained at the centre. As we move away from the central point, path difference is also changed and alternate dark and bright rings are obtained. Let us suppose that the thickness of air film ist. By using the theorem of geometry, x = x r x r = t (2R t) = (2Rt -) Sincet is very small as compare to r, therefore neglecting = 2Rt r2 = 2Rt.. (1) In thin films, path difference for constructive interference is: 2nt = (m+1/2) l Where n= refractive index for air n = 1 Therefore, 2t = (m+1/2)l .. (2) For first bright ring m = 0 for second bright ring m = 1 For third bright ring m = 2 Similarly For Nth bright ring m = N-1 Putting the value of m in equation (2) 2t = (N-1+1/2)l 2t = (N-1/2)l t =1/2 (N-1/2) l .. (3) Putting the value oft in equation (1) r2 = 2Rt r2 = 2R. 1/2 (N-1/2) l r2 = R (N-1/2) l = Where N is the bright ring number, R is the radius of curvature of the lens the light is passing through, and ÃŽÂ » is the wavelength of the light passing through the glass. Working of Newtons Ring When convex surface of a long focal length lens is placed in contact with a plane glass disk and clamped together, as shown in cross section below. Adjustment screws are tightened to secure intimate contact at the center. Between the two surfaces of glass a thin film of air is formed and when this band is viewed under reflected light from an extensive light source. We ignore reflections from the top (Plano-convex lens) and bottom (plane glass disk) as these reflections just contribute to the overall glare. Since the wave is going from a higher to lower refractive index medium, there is no phase change at the glass air surface of convex lens. Whereas at the air-glass surface of the plane disk suffers a half-cycle phase shift due to reflection. Let R be the radius of curvature of the convex lens, r distance from center and the t air film thickness. Then, = 2Rt And the radius of the bright ring is given by: = [(N +  ½) ÃŽÂ »R]  ½ Here the two glass surfaces are in close contact and there is no reflection because it is as if there were no surfaces. The reflected light is almost white in colour for first maximum, this is because the distance between the two glass surfaces is such that its almost () ÃŽÂ » for the entire spectrum. Similarly succeeding rings exhibit more and more colour. Where the thickness is odd number N of (1/4) ÃŽÂ » for green, and where blue is about (N+1) (1/4) ÃŽÂ » and red is (N-1) (1/4) ÃŽÂ » will be most monochromatic ring. Therefore blue and red at reflection minima while green is at a reflection maximum. The experimental procedure to find the radius of Newtons bright ring is as follows. The convex surface of large radius of curvature is placed in contact with a plane glass disk and clamped together Adjustment screws are tightened to secure intimate contact at the center A thin film of air is formed between the 2 surfaces of glass The thin film of air is viewed under reflected light from an extensive light source Reflections from the top ( Plano-convex lens) and the bottom ( plane glass disk) are ignored, since these reflections just contribute to the overall glare The reflections of interest involves where the surfaces in contact Since the wave is going from higher to a lower refractive index medium, there is no phase change at the glass-air surface of the convex lens Whereas at the air-glass surface of the plane disk suffers a half-cycle phase shift due to reflection. Taking R as the radius of curvature of the convex lens, the relation between the radius of the ring r and the air-film thickness t is given by r2 = 2Rt . Then radius of the nth bright ring will be given by = The Newtons ring is used to;  · Illustrate the interference fringes formed in the air film between optical surfaces.  · Newtons rings are used to determine the radius of curvature of the bi convex or Plano-convex lens  · Measure the refractive index of a substance placed beneath the same lens.  · Determine the wavelength of sodium light

Ralph Waldo Emerson vs. Walt Whitman Essay

In their respective fields, both Walt Whitman and Ralph Waldo Emerson were considered to be quintessential American writers. Their thoughts and statements regarding nonconformity and individuality were revolutionizing for the era that they lived. Thanks to them,similar thoughts and statements, are now much more mainstream and unexceptional.Although they used different tactics to get their points across, their shared opinions become evident. Both Walt Whitman and Ralph Waldo Emerson believed strongly in originality and personal expression;although the different tactics that they used to get their message across were nothing short of contrasting.In Emerson’s case, he was vehemently opposed to a society that he saw to be oppressive and unimaginative. Emerson was convinced that all of modern human civilization was in collaboration to crush his uniqueness and subjugate him to a life of a faceless cog. â€Å"Society is in conspiracy against the manhood of everyone of its members.† (P. 153) Conversely, Whitman regarded the common man with much esteem and favoritism. In his epic poem, â€Å"Song of Myself† Whitman spoke of the working class with an unusual favoring and support of their ways and lifestyle. â€Å"The sun falls on the crisply hair and mustache, falls on the black of his polish’d and perfect limbs, and I behold the picturesque giant and love him.† (P.173) Whitman encouraged the reader to lead an original and unconfirmed life. He celebrated the common man and tells the reader to be happy with their life and social stature. These ideals might seem as if completely different, but the points that they try to get across, are exactly the same. They are both stating that one should turn its back on the complex structure that is society and rather live a simple (although by no means primitive or unoriginal) life, unconstrained by conforming and strict social customs or procedures. The tones of Emerson’s poem’s and Whitman’s essay, were quite contrasting. Emerson’s essay seemed almost cold and apocalyptic contrasted to Whitman’s comparatively beautiful and uplifting poem. In Self Reliance, Emerson speaks of society with disgust and suspicion. He sees it all as a cruel masquerade that binds hapless souls to its iron will. â€Å"Society never advances. It recedes as fast on one side as it gains on another.† (P.152) In â€Å"Song of  Myself†, Whitman speaks in flourishes and silky verse’s. â€Å"You sea! I resign myself to you also – I guess what you mean, I behold from the beach your crooked fingers.† (P.180) Emerson’s essay was very philosophical and open to personal interpretation (â€Å"A foolish consistency is the hobgoblin of little minds† P. 144), while Whitman’s poem was more detailed and vividly sensual (â€Å"The beards of the young men glisten’d with wet, it ran from their long hair†, P. 173). Also notable, is the fact that Whitman spoke to the reader about what he perceives and his personal opinions. (â€Å"I guess it must be the flag of my disposition.† P. 170),while Emerson spoke more about facts that he knew to be true, leaving it up the reader to agree or not. â€Å"Another sort of false prayers are our regrets.† (P. 150) From this, it is obvious to see that their writing styles and personal tactics differed greatly when it came to persuading someone of a particular cause.Emerson and Whitman both strived for more originality in society. Whitman was dedicated to creating an authentic American conciseness through his writing, one that was not made up of cast off European procedures. Emerson was committed to freeing the minds and let loose the originality, which he saw society holding back. â€Å"Society is a joint stock company, in which the members agree, for the better securing of his bread to each shareholder, to surrender the liberty and culture of the eater. (P.140) It is evident to see that both Walt Whitman and Ralph Waldo Emersonstrongly felt the need to free, warn, or otherwise inform society of their findings and opinions. Thanks to this sense of obligation and perspective liberty, we all now get to enjoy many other informative do-gooders like them, eager to advise and enlighten us in all aspects of life. Ironically, in their attempts to free us of the torture that is society, they have unleashed a quintessential component that makes their fear and opposition to this civilization too accurate indeed.That would be telemarketing.

Guns Germs and Steel Essay

Yali asked the question of â€Å"why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had so little cargo of our own? † (Diamond 14) In other words, he is asking â€Å"what is the factor between our people and ours that causes human development to proceed at different rates? † (Diamond 16) What Yali is really asking though, is, what is this mysterious factor? According to Diamond, the basis for development is the environment around us including the resources and the native people of New Guinea don’t live in an area where a chance is provided for them to take advantage of. The natural resources are just enough for them to get by. This is why the people of New Guinea produce so little â€Å"cargo† of their own. Pizarro’s capture of Atahuallpa and destruction of the Incas made the Europeans realize what power they head, and what they could do to the rest of the world. They easily wiped out the Inca’s of 80,000 with 168 men. From the Battle of Cajamarca, Pizzaro came back to Charles I saying that Europe had the power to conquer the Americas. There were reasons Pizarro and the Europeans could conquer the Americas†¦ They had better warfare than the Incas. Pizarro’s men had armor rode horseback and used steel compared to their wooden weapons. Eurasia happened to have an abundance of edible material because of the right environment leading to the domestication of plants and animals led the people to settle down in one place instead of being nomads. When people started to settle down and bring the food to them, they started to have a surplus which led for the people to have extra jobs and it started to also support a higher population while allowing women to have more children contributing to job specialization. These specialists were not devoted to farmers or food producers but varied to priests, blacksmiths etc. Permanent agriculture societies were able to from with the food surpluses leading to empires. Some of the reason that people began to settle down and farm are because at the time many wild foods began to decrease due to hunters and gatherers killing off too many large animals leaving life unsustainable. More wild plants that could be domesticated became available at the time. Technological advances allowe3d people to harvest and store greater amounts of food that they cultivated. Human populations rose it’s not clear how much it caused food production and how much food production caused it but researchers believe there’s a connection. As populations rose, they needed to have better food supplies and started farming. The farm societies were able to drive out neighboring hunter-gatherers. A continent with long east-west axis like (Eurasia) has an advantage over continents with long north-south axes (like Africa and the Americas). The reasons it does have to do with crops and longitude. In general similar crops can grow at similar longitudes. In other words a cropped that developed in one place can be spread east to west (or west to east) but less likely to spread north and south. Epidemic diseases developed among the societies that had been farming the longest. These were Eurasian societies. Societies in the Americas, Australia, and other places had not been farming as long and lacked epidemic diseases. When Europeans came in contact with Native Americans, for example, European epidemic diseases killed huge percentages of the Native Americans. This helped the Europeans conquer and the conquest made them richer and more powerful. Therefore germs help to answer Yali’s question. The societies that did independently invent writing were those with complex hierarchies and sophisticated systems of food production. Writing was needed for politics and was generally learned by bureaucrats who had the comfort of available time and energy. As food was available to them, they had no need to hunt and gather for themselves. Since their basic needs were being met, they could focus on a higher level of existence and communication. There are two conditions in which technology may develop. The first is â€Å"mother necessity ideology† which is when a society needs something to make things easier they invent it. Technology differed from place to place because there were more people to invent and better diffusion to spread the invention. The opposite happened in the Americas because there were less people and a slower diffusion rate. Also different cultures had different ideas for change. The only way that society can emerge is through food. Such developments include jobs, such as the chief and the beginnings of government. The institutions of society changed over time based on how organized they were. They evolved based around various factors like war and other societies. They are related by diffusion. Whenever a state is conquered by another state they enforce use of their technology or exploit it. States are going to develop weapons, troops, and religion in order to make the state survive. They develop in response to need of their population size. They use these agents of conquest to become larger and to conquer other societies; and for that they need guns, germs, and steel. What Diamond is saying is that he thinks that people really should not think that history is so much different from the sciences. He is saying that the study of history can be pretty â€Å"scientific† if it is done correctly (and that some sciences are not as precise as things like chemistry). Diamond is trying to argue that historians should use what he calls â€Å"natural experiments. † He thinks that there are many â€Å"experiments† where there are two or more places that are pretty similar in many ways but which then turned out differently (like his experiment in Chapter 2). He argues that historians can use these — they can look at what was different and what was similar and how the differences led to the differences in the outcomes. Guns, Germs, and Steel Book Review I think Diamond’s central intent of writing the book is to explain how varying societies become dominate, and how certain others can become dominated. By looking at environmental conditions that caused the disparities that lead to certain societies developing guns, germs, and steel, including other technology, and forming a government necessary for conquest. He introduced the book with Yali’s question â€Å"Why is it that you white people developed so much cargo and brought it to New Guinea, but we black people has so little cargo of our own? † This question used a scientific/geographic background, and set his intent is to answer the question or inform how to answer the question. He also tries to analyze the causes of the expansion of civilizations’ in some parts of the world, since all people are physically the same what could cause some to be successful and others to die? He used archaeological and historical case studies and evidence from genetics and linguistics, he argued that technological and gaps in power are not caused by race or culture differences but by environmental differences, He used the idea of the axis as one saying that Eurasia had an east to west (or west to east) therefore having an advantage over Africa or the Americas for instance, because crops could grow at the same longitude but it was more difficult as they went north and south. Also when cultural or genetic differences have favored Eurasians like for example written language or resistance to epidemic diseases he says these advantages occurred because of the influence and geography on societies and cultures and were not inherited as genes from Eurasian ancestors. Diamond’s book argues that the differences in progress for different societies around the world do not result from one group being smarter or more resourceful than another. Rather, he focuses on the impact of geography — whether food and other key items were plentiful, whether and how disease spread, and how these developments led to different levels of industrialization, and wealth The book â€Å"Guns, Germs, and Steel† was very well written in the sense that Diamond had a question in which was the foundation of the book, he throughout the book acquired evidence and explanations and ideas of how to answer the question. The book had evidence to back it up by explaining how Eurasia had a better opportunity being west to east meaning they had better crop farming. Which led to a growing civilization and soon conquest. The book wasn’t exactly dull or boring but it wasn’t exciting or entertaining either. It was like any other history book it asked a question, then went on to the point. There was an explanation of the main topic which was Yali’s question and evidence that dealt with answering the question. From beginning to end, Diamond stresses that he realizes that efforts to compare societies have frequently been used by racists or nationalists to belittle groups or justify mistreatment of them. He argues that his analysis is in fact anti-racism at work because it shows that the white people who enjoy the comforts of modern life are ultimately luckier than, not more deserving than, people in impoverished nations.

Essay On Video Game Violence - 1377 Words

Have you ever had the urge to harm or kill someone after playing a game of football? People of all ages love to play this sport whether it be for fun or bragging rights. We watch two people almost tear each other apart in boxing or Ultimate Fighting Championship (UFC). Chances are you probably just looked at these events and went on with your day afterwards. We have faced dangerous events such as wars, natural disasters, and terrorist attacks. What these events have in common is that they are actually real examples of violence. With events like these around, why would someone take the time to blame a piece of digital media that is only meant for fun? Parents, Ralph Nader a political activist and even our current president Donald Trump all†¦show more content†¦Andrew Leonard, who is a technology reporter, editor, blogger, and staff writer at Salon, speaks about how his very own son works together with people while playing games. The game his son plays is Minecraft. This is a game where you can build huge structures, fight monsters, interact with other players, and more. Andrew had this to say about gaming with others: â€Å"The platform and the mode of interaction make a big difference—something that explains why your grandmother might be willing to play a game on her iPhone while never daring to pick up an Xbox 360 game controller. So cool it with the cesspool naysaying: Games that encourage collaboration and community feed fountains of positivity.† (Andrew Leonard, 2013). We already established that video games can bring people together, but they can also help their players remain healthy. Video games can also be seen as a virtual therapist or doctor. The type of game that will offer therapeutic relief will depend on the person. It could be a racing game, because some people feel that driving helps them feel better, or it could be a strategy game that exercises your brain. No matter what game is used to help the person feel better, it wi ll still help improve their health. There are plenty of games that promote physical fitness. Game systems such as the Wii, Xbox, and PlayStation all have external devices that can be hooked up to them so you can play the moreShow MoreRelatedViolence of Video Games Essay1204 Words   |  5 Pagescompare the â€Å"overconsumption† of video games with violence to the above with added danger. The fact that video games are addictive as can be seen by anyone with experience of playing or the people in our lives who fell under the spell of video games. Obviously, they get absorbed and obsessed over the virtual world and sometimes forget their responsibilities and obligations. The virtual world stealing peoples’ lives in that manner is another major topic. 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