Refractive index of different liquids using hollow prism. The experiment would be suitable in the undergraduate physics laboratory. It is defined as, where c is the speed of light in vacuum and v is the phase velocity of light in the medium. All faces are transparent and opposite faces are parallel. This note describes an experiment for determining the refractive index of glass. This is the cause of chromatic aberration in simple lenses. Different glass types exhibit different dispersion curves, as shown below. Apparatus three glass slabs of different thickness but same material, a travelling microscope, lycopodium powder. Pdf determination of refractive index of optically transparent.
Spectrometer, refractive index of the material of a prism. In this experiment, why is there no refraction of the light ray on the circular side of. The abbe refractometer is a classic optical instrument used to measure the refractive index of liquids or solids. An approximate measurement of the refractive index of a transparent glass may be made using the becke line technique. Aim the experiment is to enable the students to observe the image formed of an optical pin in the glass block and also use the data obtained to determine the refractive index of the glass block. As light passes through the interface between two mediums of different refractive indices, it bends as shown in fig. In most applications, the index of refraction of air can be taken to be one, with. The project should include some background information on snells law, all the steps taken in the experiments, key experimental results and a conclusion about the experiment including identification of the unknown solid from the refractive index. A simple method to determine the refractive index of glass.
It carries a vernier scale along the main scale and can be moved upward or downward. The refractive index determines how much the path of light is bent, or refracted, when entering a material. Aim a laser at the glass block so that it emerges on the opposite site. For example, a glass has a refractive index of about 1. Using grim3, repeat measurements produce results with a standard deviation of, typically, 0. The purpose of this experiment is to study the phenomenon of dispersion i. Refractive index or the index of refraction is the ratio of the speed of light in vacuum or air to the speed of light in a transparent material. The prisms are housed, one in each half of a hinged water jacket used for making index vs. Measuring the refractive index understanding standards. A new method for measuring the refractive index of glass. For estimating the refractive index of sugar glass see the reference to the feyman lecture covering refractive index of sucrose already mentioned in notes from the pfund method experiment. Opti 20 2l geometrical and instrumental optics lab 101. The experiment is practically easier using a hemicylindrical prism of glass, with the beam entering from the curved side and travelling along a radius. It turns out that n is smaller for long wavelength red light and larger for short wavelength blue light.
Remove the glass block, draw in the emergent ray and the refracted ray and measure the angle of refraction, r. Pdf a new method for measuring the refractive index of glass. The refractive index of glass is a function of the wavelength of light, a property known as. Lab index of refraction of glass newton local schools. Many materials have a wellcharacterized refractive index, but these indexes depend strongly upon the frequency of light.
That is, blue light is bent more by glass or plastic lenses and red light is bent less. Pdf measuring refractive index of glass by using speckle. This property is very helpful in designing optical lenses as it allows to calculate the bend angle of beam of light when passes. Concentration in most solutions, the concentration of solute in a solvent can be determined by measuring the refractive index n d. Use of the noparallax technique to locate an apparent image of a real object 2. By varying temperature to alter the refractive index of a calibrated oil, the ri of an immersed fragment of glass can be determined at the point of null refraction, the point at which the refractive indices of glass and immersion oil match. Place a glass block on a sheet of paper and draw its outline.
The speed of light in a medium depends on the medium itself, temperature and wavelength. Measurement of the refractive index and dispersion of. In this experiment, you will measure the dispersion curve of a dense flint optical glass. Determination of the refractive index of a glass block. The ray of light is incident on glass at an angle of 35, having refractive index 1. Determination of refractive index of glass and water by. The aim of the experiment is to study the refraction index of a glass.
Refractive index lab worksheet example answers pdf teach. Pdf it is well known in optics that the refractive index is an important optical parameter of material. A slab is a piece of transparent material with rectangular faces. Refractive index using hollow cell see the theoretical data below, based from snells law, using n1.
Repeat the experiment for the other angles of incidences, 0 o, 30 o, 45 o and 60 o tabulate the values of the angles i and r, and also using the calculator, the values of sin i and sin r. Different glasses exhibit different dispersion curves, as shown below. Determination of the refractive index of a liquid using the apparent depth method pack contents. Gonlon, mineralogisches i nstitut, j niversity of erlangen n ii. The refractive index is a unitless number, between 1. To determine refractive index of a glass slab using a travelling microscope. Photo b shows the same piece of glass immersed in water. Sc physics,1st year chennai mathematical institute 17. Place the plexi glass triangle on a sheet of paper and trace around the edges. Determination of the refractive index of a liquid using the. To determine refractive index of a glass slab using a travelling microscope travelling microscope is a compound microscope that is fitted on the vertical scale.
Since it is necessary to use a computer program when determining the refractive index, students could be given the opportunity of. Most glass makers produce this glass under slightly different names. Measurement of the refractive index and dispersion of optical. To determine the refractive index of various liquids in a hollow prism. Measurement of refractive index using a michelson interferometer. Place the plexiglass triangle on a sheet of paper and trace around the edges. Your experimental results should be precise enough to. The refractive index n of a transparent material can be determined by measuring the angle of incidence and the angle of refraction as a ray of light enters, or leaves the material. Standard refractive index measurements are taken at the yellow doublet sodium d line, with a wavelength of 589 nanometers. Bk7 optical glass bk7 is a very popular crown glass. Pdf the present experiment discusses, presumably the most basic. Dec 02, 2016 to determine refractive index of a glass slab using a travelling microscope aim to determine refractive index of a glass slab using a travelling microscope. The refractive index n of a medium is defined as the ratio of speed of light in vacuum c in to that in the medium v. Is defined as the ratio of velocity of light in vacuum to the velocity of light in a substance at same wave length.
Refractive index determination of a small glass fragment refractive index of small pieces of glass can be determined using commercially available liquids whose refractive indexes are known a b c photo a shows a small piece of pyrex glass not immersed in a liquid. By knowing the refractive index of a substance you can also know the speed of light in that substance. In this activity we will use the gem refractometer to measure the refractive index of common glassy. Principle and task the refractive indices of liquids and glass are determined by refraction of light through the prism at minimum deviation. A semicircular, cylindrical, glass block,2 90 mm in diameter, is placed on a sheet.
Ask your doubt of refractive index and get answer from subject experts and students on topperlearning. Index of refraction n of air introduction in this experiment you will measure the index of refraction of air by comparing the optical path lengths of two columns of air of equal physical length but at different pressures. The relation between the refractive index and the concentration depends on the. The theory underlying the grim technique is described and, furthermore, the results of refractive indices determinations for glass. Pdf a method to measure the refractive index of an optically flat, regularly shaped slab of glass. The instrument used to compare optical path lengths is the michelson interferometer. Determination of the refractive index of a glass block using. In this experiment, the independent variable is the angle of incidence, and the dependent variable is the angle of refraction. Refractive index lab worksheet example answers pdf. In this experiment, you are required to the refractive index of an acrylic determine. If the refractive index of glass for light going from air to glass is 32,find the refractive index of air for light going from glass to air. Fasten a sheet of paper to a drawing board or flat surface into which pins can be pressed easily. To verify snells law and measure the refractive index of a solid diagram apparatus laser glass block protractor procedure 1.
Three glass slabs of different thickness but same material, a travelling microscope, lycopodium powder. The accuracy of the experiment is fundamentally determined. Use these angles to calculate the index of refraction of the material. A small chip of the glass having a sharp edge is immersed in a refractive index oil standard and placed in focus in a transmission microscope. On errors of reflectivity measurements and of calculations refractive index n and absorption coefficient k honsr prr. Dispersion, a decisive factor for optical applications, explains the entire refractive index. Apparatus and material required a travelling microscope, a glass slab, lycopodium powderchalk dust and a paper. Light is shone through a glass block at various angles.
Since n varies with wavelength, the angle of minimum deviation also varies, but it is constant for any particular wavelength. The measuring and illuminating prisms are usually of 306090construction, made from glass, the refractive index of which is higher than the upper limit of the. Dec 14, 2009 an experimental demonstration of snells law of refraction. The two halves of the water jacket, when brought together, enclose a thin film of the liquid being measured. An experimental demonstration of snells law of refraction. Refractive index, also called index of refraction, measure of the bending of a ray of light when passing from one medium into another. The refractive index determines how much light is bent, or refracted, when entering a material. To verify snells law and measure the refractive index of a solid. Scattered light and reflections occur at glassair surfaces, at cemented.
The aim of this experiment is to find the refractive index of a glass prism. The focal plane is then raised by raising the objective. To find refractive index of glass ing travelling microscope. Abbe refractometers are routinely used in modern chemistry labs for.
The index of refraction of glass varies with its composition and with the wavelength of the light incident on the glass. A calibrated paper template allows the angles of incidence and refraction to be. Refractive index a refractometer measures the extent to which light is bent i. Measuring refractive index of glass using gem refractometer. Determination of the refractive index of glass and a liquid using a travelling microscope. Draw the incident and emergent paths of the laser on the paper. To verify snells law and measure the refractive index of. Determination of the refractive index of a liquid using. If i is the angle of incidence of a ray in vacuum angle between the incoming ray and the perpendicular to the surface of a medium, called the normal and r is the.
Sph 2182 physics for life sciences b9 refractive index jkuat. To determine refractive index of a glass slab using a. Experiment aim to determine refractive index of a glass slab using a travelling microscope. This is described by snells law of refraction, n 1 sin. Repeat the experiment for the other angles of incidences, 0 o, 30 o. Determination of the refractive index of the material of a prism using sprectometer debangshu mukherjee b. Ordinary crown glass, when illuminated by white light, has a refractive index of 1. The angle at which minimum reflectionor zero for properly polarized lightobserved is the brewster angle and tan of the brewster angle will give refractive index of the glass.
The experiment results show that the peaks position of the absorption shift forward the long wavelength and the refractive indexes increase with. The refractive index also depends on the wavelength colour of the light ray. In optics, the refractive index or index of refraction of a material is a dimensionless number that describes how fast light travels through the material. The index of refraction is, in general, a function of the wavelength of the light. Refractive index of different liquids using hollow prism physics kids projects, physics science fair project, pyhsical science, astrology, planets solar experiments for kids and also organics physics science ideas for cbse, icse, gcse, middleschool, elementary school for 5th, 6th, 7th, 8th, 9th and high school students. Refractive index using hollow cell and percent light transmission measurement. The refractive index and dispersion of optical glass that is used for lenses and for other refmctive purposes are the most important char acteristics of such. Sodalime glass is the most prevalent type of glass, used for windowpanes and glass containers. Sodalime glass accounts for about 90% of manufactured glass. Pn junction diode characteristics experiment edunovus online smart. Draw accurately the outline of the rectangular glass block.
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