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

Defining Moments in Song of Solomon, Push, and Narrative of the Life of Frederick Douglas :: comparison compare contrast essays

Defining Moments in Song of Solomon, Push, and Narrative of the Life of Frederick Douglas      Ã‚  Ã‚   For those who bask in the light of privilege in the dominant culture, they take for granted their right to assert themselves and to be acknowledged as "somebody who matters". For those who live in the shadowy margins (such as the American poor and/or minorities), they experience the systematic denial of the basic human rights - to live at one's fullest potential, in other words, an outright denial from living a "dignified life". Such a denial might cause one to feel "voiceless and choiceless" (Objective 1b). It has been the minority's experience, (historically and in the present day) that the right to achieve one's full potential is kept just out of reach. Minorities must first fight for survival. Then, if there is enough energy and hope remaining, they can strive to utilize vehicles of assimilation or resistance (Objective 4) in order to carve a place for themselves in the world. However, this does not mean that a full realization of the "American dream" is even possible. For every small victory, there remains a bitter aftertaste. In other words, for every step gained, there is a "personal or cultural sacrifice" (Objective 4). Meanwhile, on the journey to freedom, the individual is plagued with 'ghosts' of the past. These 'hauntings' can appear in the form of individual/family oppression: (knowledge of emotional pain, physical violence) or in the form of a historical haunting: (i.e. knowledge that your ancestor was a slave; the traditional family unit broken)(Objective 3). These disturbances continue to surface and demand to be worked through, thus a 'haunting' is another factor that holds one back from achieving their full potential.    Whether oppression comes from a large, historical institution such as slavery, or from inter-family abuse, it is the process of suppression that I am exploring in this essay. The process of oppression is where families or institutions withhold or prevent one's self-worth or self-identity to develop. I will explore the personal journeys of the following characters; 1) Frederick Douglas from The Classic Slave Narratives, 2) Milkman from Song of Solomon, 3) Precious from Push, noting how they all share a common path through the darkness of oppression towards the ability to assert their self-identity.

Eco Friendly Structures

Major elements of green building design which are: Sustainable Site Design Key Principles: Minimize urban sprawl and needless destruction of valuable land, habitat and green space, which results from inefficient low-density development. Encourage higher density urban development, urban re-development and urban renewal, and brownfield development as a mearns to preserve valuable green space. Preserve key environmental assets through careful examination of each site.Engage in a design and construction process that minimizes site disturbance and which values, preserves and actually restores or regenerates valuable habitat, green space and associated eco-systems that are vital to sustaining life. Water Quality and Conservation Key Principles: Preserve the existing natural water cycle and design site and building improvements such that they closely emulate the site’s natural â€Å"pre-development† hydrological systems. Emphasis should be placed on retention of storm water an d on-site infiltration and ground water recharge using methods that closely emulate natural systems.Minimize the unnecessary and inefficient use of potable water on the site while maximizing the recycling and reuse of water, including harvested rainwater, storm water, and gray water. Energy and Environment Key Principles: Minimize adverse impacts on the environment (air, water, land, natural resources) through optimized building siting, optimized building design, material selection, and aggressive use of energy conservation measures. Resulting building performance should exceed minimum International Energy Code (IEC) compliance level by 30 to 40% or more. Maximize the use of renewable energy and other low impact energy sources.Indoor Environmental Quality Key Principles: Provide a healthy, comfortable and productive indoor environment for building occupants and visitors. Provide a building design, which affords the best possible conditions in terms of indoor air quality, ventilation , thermal comfort, access to natural ventilation and daylighting, and effective control of the acoustical environment. Materials and Resources Key Principles: Minimize the use of non-renewable construction materials and other resources such as energy and water through efficient engineering, design, planning and construction and effective recycling of construction debris.Maximize the use of recycled content materials, modern resource efficient engineered materials, and resource efficient composite type structural systems wherever possible. Maximize the use of re-usable, renewable, sustainably managed, bio-based materials. Remember that human creativity and our abundant labor force is perhaps our most valuable renewable resource. The best solution is not necessarily the one that requires the least amount of physical work.

“Children are best raised by their natural father and mother” †Critically Analyse The WritePass Journal

â€Å"Children are best raised by their natural father and mother† – Critically Analyse Abstract â€Å"Children are best raised by their natural father and mother† – Critically Analyse ) where the tribunal refused to allow an adoption agency from discriminating on the grounds of same-sex couples in adoption procedures. This confirmed the earlier decision of the ECtHR in Karner v Austria (2003) which stated that there need be significant and convincing reasons for discriminating against same-sex couples. It is clear therefore that moving towards a non-discriminatory society which recognizes equal rights for same-sex couples with regards to family life is a right which is currently seeing significant attention. In the judgment of X, Y Z v UK (1997), the ECtHR held that in determining whether a specific relationship may amount to family life, there is the need to consider a number of relevant factors. These factors include whether the couple cohabit, the duration of their relationship and whether there is a demonstrated measure of commitment to one another by the parents by having children together or any other demonstrable means. This was confirmed in the judgment of Fitzpatrick v Sterling Housing Association (1999) the court recognized that establishing the existence of a family life required the examination of factors such as the mutual inter-dependence between spouses, a commitment to sharing of lives together, the existence of caring and love-filled relationships, mutual commitment and the support that is rebuttably presumed to exist in marriage type relationships. The existence of a family life therefore that is necessary for the determination of the best interests of the child, is on e which does not necessarily include traditional parental roles, but rather the de facto existence of close personal relationships which define the relationship between a parent and a child. It stands to reason that the existence of these relationships will be best for the child, regardless of whether they exist in a same-sex parented family. Conclusion The question of whether it is in a child’s best interests to be raised by their natural mother and father is one which is currently a topic of widespread debate, particularly with regards to the question of adoption by same-sex couples. It is clear that the echoes of legal discrimination of same-sex couples is a topic that is garnering significant attention and the injustices that remain are being challenged and abolished. The significance of these decisions cannot be understated for the purposes of children’s and family law, as essentially this serves as a paramount recognition by the judiciary, based on legislated grounds of human rights, that a family unit does not necessarily consist of a natural father and mother to the exclusion of same-sex parented families. The essential inquiry in this regard is into the best interests of the child and although there is still a measurable amount of discrimination against same-sex couples, it has been shown that same-sex parents are not contradictory to these interests. Providing a stable and loving environment for raising children is in the best interests of a child and whether this is provided by same-sex parents or heterosexual parents is of little consequence by comparison to the factual personal relationships that exist in these families. References Primary Sources Legislation The Children’s Act 1989 The Children’s Act 2004 Convention on the Rights of the Child, Adopted and opened for signature, ratification and accession by General Assembly resolution 44/25 of 20 November 1989, Entry into force 2 September 1990, in accordance with article 49. The European Convention on Human Rights The Human Rights Act 1998 Common Law Catholic Care (Diocese of Leeds) v Charity Commission for England and Wales. [2012] Upper Tribunal, Appeal number FTC/52/2011 Fitzpatrick v. Sterling Housing Association Ltd [1999] 4 All ER 705 K and T v Finland [2001]36 EHRR 18 Karner v Austria [2003] 38 EHRR 528 Mazurek v France [2000] 42 EHRR 9 R (Williamson) [2005] UKHL 15 Re: Compatibility of the Adoption Order (NI) with the ECHR [2012] NIQB 77 Salgueiro da Silva Mouta v Portugal [1999] 31 EHRR 47 X, Y Z v UK [1997] 24 EHRR 143 ZH (Tanzania) v SSHD [2011] UKSC 4 Secondary Sources Haringey Local Safeguarding Childrens Board (2009) Serious Case Review ‘Child A’ (ref: March 2009) London: Department for Education Hodson, L. (2008) The Rights of Children Raised in Lesbian, Gay, Bisexual or Transgender Families: A European Perspective. IGLA: Europe Lundy, L. (2007) Voice Is Not Enough: Conceptualising Article 12 of the United Nations Convention on the Rights of the Child. British Educational Research Journal, Vol 33, Issue 6, pp. 927 942 Wintemute, R. Andenas, M. (2001) Legal Recognition of Same-Sex Partnerships: A Study of National, European, and International Law. Hart: Oxford

Ontario Harmonized Sales Tax (HST)

Ontario Harmonized Sales Tax (HST) What is the Ontario Harmonized Sales Tax? As part of its 2009 provincial budget, the Ontario government tabled a bill on November 16, 2009 to introduce a harmonized sales tax (HST) in Ontario. The harmonized sales tax being proposed by Ontario will combine the eight percent provincial sales tax with the five percent federal goods and services tax (GST) to create a single 13 percent harmonized sales tax (HST) administered by the federal government. The Ontario HST is scheduled to take effect July 1, 2010. Why is Ontario Switching to the HST? The Ontario government says Ontarios current dual tax system puts Ontario businesses at a competitive disadvantage and implementation of a single sales tax would bring the province into line with the most efficient form of sales taxation around the world. They say the tax reform being proposed, including the HST, will create jobs and position the Ontario economy for future growth as the province emerges from the economic downturn. They also claim the single sales tax will reduce paperwork costs for business by more than $500 million a year. Tax Relief to Offset the Ontario HST The 2009 Ontario budget will provide $10.6 billion over three years in personal income tax relief to help consumers through the transition to the single sales tax. This includes personal Ontario income tax cuts and direct payments or rebates. It will also provide $4.5 billion in business tax relief over three years, including reducing the corporate income tax rate to 10 percent over three years, cutting the small business tax rate and exempting more small and medium-sized businesses from corporate minimum tax. What the Ontario HST Means to Consumers For the most part, consumers will not notice a large change in prices. However, there are many items currently exempt from the provincial sales tax that will no longer be exempt. They include: gasolineheating fuelselectricitytobaccopersonal services, such as haircuts, membership fees for clubs and gyms, magazines, taxi fares, professional services for lawyers, architects, and accountants, and real estate commissions. The HST will not be charged on: basic groceriesprescription drugssome medical devicesmunicipal public transithealth and education serviceslegal aidmost financial serviceschild caretutoringmusic lessonsresidential rentscondo fees    Currently, the PST is not applied to those items. There will still be a few exemptions from the provincial portion of the sales tax: childrens clothing and footweardiaperschildrens car seats and car booster seatsfeminine hygiene productsbooks (including audio books)prepared food and beverages sold for $4.00 or lessprint newspapers The Ontario HST and Housing No HST will be charged on residential rentscondo feespurchase of resale homes    The HST will be applied on the purchase of new homes. However, homebuyers will be able to claim a rebate of some of the provincial portion of the tax for new homes priced up to $500,000. The rebate for new primary residences under $400,000 will be six percent of the purchase price (or 75 percent of the provincial portion of the tax), with the rebate amount reduced for homes priced between $400,000 and $500,000. Buyers of new residential rental properties will receive a similar rebate. The HST will apply to ​real estate commissions.

The Main Issues Involved in Iranians Annotated Bibliography

The Main Issues Involved in Iranians - Annotated Bibliography Example This research will begin with the review of â€Å"Irangeles: Iranians in Los Angeles† written by Ron Kelley, Jonathan Friedlander, and Anita Colby. The researcher states that in a novel format, this work is a combination of essays, interviews, and photographs of the Iranian immigrants in Southern California. According to the research findings, the work shows how Iranian women in the U.S try to adopt the Western culture and to deny their Iranian roots. This work  helps in explaining the general tendency among the Iranian women writers after the revolution to present themselves as liberal, freedom-loving, and democratic human beings who have nothing to do with terrorism and extremism. The present research has identified that Nesta Ramazani is another female contemporary of Satrapi. With an Iranian father and English mother, Nesta narrates her life in Iran before and after the revolution. This paper illustrates that the writer faces a lot of pressure in the fundamental Iranian society, and manages to struggle through with luck and hard work.   The work shows how Iranian, Islamic, and Western cultures collide, mingle, and influence the lives of people in Iran. The autobiography by Nesta is used in two ways. Firstly, it helps understand the influence of fundamentalism on Iranian people, and secondly, it helps explore the general tendency among Iranian women writers to show adherence to the West.  

Psychology Essay Example | Topics and Well Written Essays - 500 words - 1

Psychology - Essay Example During the development of the personality the primary caregiver must connect with positive regard to the child in order for his or her personality to develop correctly. This becomes the basis for congruence and the personality is more directly connected between the real self and the perceived self. This Rogers perceives as a required psychological adjustment, â€Å"...which is characterized by an openness to experience without defensiveness, congruence between self and experience, and living by an internal locus of evaluation rather than by externally determined conditions of worth." (Demorest 144) His methods puts the clients back in control and Rogerian Therapy is basically a client centered non-directive approach whereby the therapist acts as a conduit for the client so that he can view him or herself more clearly. As human beings we have an "idea" or concept of who we are and what we really should be, hence we create an Ideal Self that we constantly strive for, often in vain. If the perceived self, our own self-image, is not aligned with the actual self, how we really are, there will always be personality problems and dysfunction as one relates to one's self and the rest of the world. (Kail & Wicks).