Interference fringes and newtons rings in this lab, we shall examine some interference effects. A slightly convex lens is placed above an optical flat. If you cannot ensure flatness without glass, you may want to try a fluid which matches the refractive index of the glass. View newtons rings from phys 1222 at university of the west indies at st. The radius of curvature of a convex lens is given by. Experiment 4 to determine the wavelength of monochromatic light sodium light by newtons ring experiment 5 to determine the wavelength of sodium light source using plane transmission grating experiment 6 to verify inverse square law of light using a photo cell.
Pdf newtons rings is a phenomenon in which an interference pattern is created by the reflection of light between two surfacesa spherical surface and. Experiment 4 to determine the wavelength of monochromatic light sodium light by newton s ring experiment 5 to determine the wavelength of sodium light source using plane transmission grating experiment 6 to verify inverse square law of light using a photo cell. Applications of newtons ring engineering physics class. Practice tests and free video lectures for physics, chemistry. Exp2 to determine the refractive index of a liquid by using newtons rings apparatus. Subscribe to our youtube channel to watch more lectures. To determine the wavelength of sodium light by newtons ring method. The bright and dark patterns that appear at the interfaces of two nominally flat pieces of glass are called fizeau fringes. The ring pattern may not be extremely sharp and, thus, blurred. The experimental setup used for the experiment is shown in. Ring shaped fringes are produced by the air film existing between the convex surface of a long focus planoconvex lens and the plane of glass plate. To determine the wavelength of sodium light using newtons. Ue4030350 ue4030350 exp riment procedure ve newtons rings with monochroobser.
Newtons rings is a phenomenon in which an interference pattern is created by the reflection of light between two surfacesa spherical surface and an adjacent touching flat surface. To measure the radius of curvature of a planoconex lens using newton s rings apparatus apparatus. To observe newton rings formed by the interface of produced by a thin air film and to determine the radius of curvature of a planoconvex lens. Newton s rings are the interference rings found between any two surfaces with different light velocity and making the phase difference between the reflected and refracted light waves making for interference. You can find a short guide for the program from manual of. Newton s rings 38009 aim of the experiment to study the formation of newton s rings in the airfilm in between a planoconvex lens and a glass plate using nearly monochromatic light from a sodiumsource and hence to determine the. A plano convex lens of large radius of curvature, optical arrangement for newtons rings, plane glass plate, sodium vapour lamp and traveling microscope.
It is named after isaac newton, who investigated the effect in his 1704 treatise opticks. Exp4 to find the thickness of a thin sheet of paper air wedge experiment. The two interfering beams, derived from a monochromatic source satisfy the coherence condition for interference. A mercury lamp, which emits predominantly at the wavelength of. To determine the wavelength of sodium light by newtons ring. Using the newtons rings apparatus, to measure the diameter of the rings at different wavelengths and. Concept of newtons rings for engineering physics b. To measure the radius of curvature of a planoconex lens using newtons rings apparatus apparatus. An air wedge, formed between the spherical surface and an optically flat surface, is. Exp3 to find the radius of curvature of planoconvex lens using newtons rings experiment, given. Newtons rings are interference patterns formed by light incident on the thin film of air between a convex lens and a flat or between two suitable lenses. They are formed as a result of interference between light waves reflected from the upper and lower surfaces of the. This page supports the multimedia tutorial interference.
By employing sodium light whose mean wavelength is 5893a, r can. An air film of varying thickness is formed between the lens and the glass sheet. May 22, 2012 doing so, newtons rings should now be viewable at the focal plane of the traveling microscopes eyepiece. Homework statement in a newtons rings experiment, involving a curved lens on a glass surface, what might have happened to the setup to see a bright spot at the centre.
Setup and procedure the newtons rings experiment is set up as shown in fig. Doing so, newtons rings should now be viewable at the focal plane of the traveling microscopes eyepiece. These circular fringes were discovered by newton and are called newtons rings. Newtons rings title newtons rings abstract in this. In this experiment the radius of the curvature r of a convex lens was determined. In a newton s rings experiment the diameter of the 15 th ring was found to be 0. Modified newtons rings experiment has been made simpler by the use of tracker software by ca pturing the fringes using a ccd camera. Newton s rings are interference patterns formed by light incident on the thin film of air between a convex lens and a flat or between two suitable lenses.
Formation of fringes when a planoconvex lens with large radius of curvature is placed on a plane glass plate such that its curved surface faces the glass plate, a wedge air film of gradually increasing thickness is formed between the lens and the glass plate. Homework statement newtons rings can be seen when a planoconvex lens is placed on a flat glass surface. Apr, 2008 homework statement in a newton s rings experiment, involving a curved lens on a glass surface, what might have happened to the setup to see a bright spot at the centre. Newtons rings is a phenomenon in which an inteference pattern is created by the reflection of light between two surfacesa spherical surface and an adjacent touching flat su. In the traditional version of newton s rings, a slightly convex lens is placed above a flat glass plate or optical flat. Move the microscope across the rings by twisting the small knob on its right. The chief source of errors and fairly perfect and practical meth eds of treatment are presented. Traveling microscope, sodium vapour lamp, planoconvex lens, plane. Newtons rings 38 discussion i the newtons ring experiment can be also used to find the wavelength of a monochromatic light. Dec 07, 2011 homework statement newton s rings can be seen when a planoconvex lens is placed on a flat glass surface. The thin film in this case is provided by an air gap between a glass plate and a planoconvex lens. For a normal incidence of monochromatic light, the path difference between the reflected rays see fig. The simulation virtualizes the newtons rings experiment.
To study the formation of newtons rings in the airfilm in between a planoconvex lens. Consider a ring of radius r due to thickness t of air film as shown in the. If the radius of curvature of the lens is 100 cm, find the wave length of the light. Newtons ringsformation of newtons ringsthin filmradius. When viewed with monochromatic light, newtons rings appear as a series. Py2107 newtons rings physics 2107 newtons rings experiment 5. The user can view the effect of newtons rings formed when the medium changes.
A planoconvex lens of large radius of curvature, optical arrangement for newtons rings, plane glass plate, sodium lamp and travelling microscope. Newtons rings can be explained on the basis of wave theory of. Antinewton glass may cause a granular pattern in the scanned file which is even worse than rings. To observe newton rings formed by the interface of produced by a thin air film and determine the radius of curvature of a planoconvex lens. To find the wavelength of sodium light by newtons ring. In this experiment you will learn about thin film interference using a system of lenses to produce concentric bright and dark interference fringes on a white screen. Newtons rings are the circular interference pattern first discovered by newton. The essential geometry for producing newtons rings is shown in the figure below. The reason that the centre is almost always dark is that the classic newton s rings experiment simply involves putting the convex lens in contact with the reference optical flat. After this few drops of liquid of refractive index is placed on the glass plate. The attempt at a solution well i know that normally we get a dark spot at the centre because of the lambda2 phase.
Newton s rings are the circular interference pattern first discovered by newton. Thanks for contributing an answer to physics stack exchange. A ray ab incident normally on the system gets partially reflected at the bottom curved surface of the lens ray 1 and part of the transmitted ray is partially reflected ray 2 from the top surface of the plane glass plate. Different ring pattern can be seen by changing the radius of curvature of the lens and wavelength of light source components. Find wavelength of sodium light by newtons rings, physics.
The newtons rings experiment is set up as shown in fig. This experiment investigates newtons rings using transmitted light from a mercury lamp which has been rendered monochromatic with the aid of interference filters. Newtons rings is an interference pattern caused by the reflection of light between two surfaces a spherical surface and an adjacent flat surface. Newtons rings, in optics, a series of concentric light and darkcoloured bands observed between two pieces of glass when one is convex and rests on its convex side on another piece having a flat surface. Alternate dark and bright rings formed due to presence of air film when plano convex lens is placed on glass plate is called newtons rings. Experiment 8 to determine the wavelength of sodium light using newton s rings please read additional instructions on the bench for setting up the pc and camera for this experiment introduction newton s rings are interference fringes of equal thickness which are produced in the air. Newtons rings are the interference rings found between any two surfaces with different light velocity and making the phase difference between. Newtons experiment with the rotating vessel of water simply informs us that the relative rotation of the water with respect to the sides of the vessel produces no noticeable centrifugal forces, but that such forces are produced by its relative rotations with respect. The reason that the centre is almost always dark is that the classic newtons rings experiment simply involves putting the convex lens in contact with the reference optical flat. The interference pattern is focussed onto the screen with the help of an objective lens.
Newton s experiment with the rotating vessel of water simply informs us that the relative rotation of the water with respect to the sides of the vessel produces no noticeable centrifugal forces, but that such forces are produced by its relative rotations with respect to the mass of the earth and other celestial bodies. But avoid asking for help, clarification, or responding to other answers. Experiment 8 to determine the wavelength of sodium light using newtons rings please read additional instructions on the bench for setting up the pc and camera for this experiment introduction newtons rings are interference fringes of equal thickness which are produced in the air. Pdf newtons rings is a phenomenon in which an interference pattern is created by the. For a particular lens with an index of refraction of n 1. Record the diameters of the dark rings as carefully as possible, using the vernier scale on the microscope. Abstract this experiment looks to investigate the physical optics of the interference pattern called newtons rings and calculate the wavelengths of various filters as well as the. In this case, the radius of curvature of the convex surface of the given lens is supplied or is determined otherwise. Engineering physics lab manual pdf ep lab manual pdf. Monochromatic light is used to illuminate the lenses. Well you are someone who is not a pure science enthusiast, are you.
When a light ray is incident on the upper surface of the lens, it is reflected as well as refracted. The errors and various causes in the experiment of measuring lens curvature diameter using newton ring are analyzed and discued. This experiment investigates newtons rings using transmitted light from a mercury lamp which has been rendered monochromatic with the aid of interference. The occurrence of the newtons rings can be explained on the basis of wave theory of light an air film of varying thickness is formed between the lens and the glass of sheet when a light ray is incident on the upper surface of the lens, it is reflected as well as refracted. This problem can be easily overcome by adjusting focusing the traveling microscope eyepiece relative to the plano convex lens since it was focused on the glass plate. Newtons rings setup, physics education 22, 3, 195202. Traveling microscope, sodium vapour lamp, planoconvex lens, plane glass plate, magnifying lens. Here we explain the phenomenon and analyse its geometry. Newtons rings apparatus indosaw industrial products pvt.