RESEARCH ON STUDY OF CONCENTRATION DEPENDENCE OF REFRACTIVE INDEX OF OIL USING A NOVEL TECHNIQUE

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1 RESEARCH ON STUDY OF CONCENTRATION DEPENDENCE OF REFRACTIVE INDEX OF OIL USING A NOVEL TECHNIQUE Department of Physics, Mid Western University, Campus of Science and Technology dhakaldharma605@gmail.com ABSTRACT: There are different methods to determine the refractive index of salts, solids (crystalline) and liquids. These methods are quite tedious. A simple and reliable method is developed by developing mathematical equation for aqueous solutions. The technique was employed to study refractive index of oil by varying concentrations. A hallow prism is used along with optical spectrometer at room temperature to determine refractive index of oil. The results were compared with the results obtained from optical spectrometer and it was found that this technique is quite reliable and can be safely used in the study of the optical properties of any transparent liquids and solids. Keywords: optical spectrometer, refractive index, hollow prism

2 Table of Contents INTRODUCTION...3 LITERATURE REVIEW...4 MATERIAL AND METHODS...5 RESULTS AND DISCUSSION...6 CONCLUSION...6 Reference...7

3 INTRODUCTION The refractive index is a very important property of the components of any optical instrument that uses refraction. It determines the focusing power of lenses, the dispersive power of prisms, and generally the path of light through the system. It is the increase in refractive index in the core that guides the light in an optical fiber, and the variations in refractive index that reduces the reflectivity of a surface treated with an anti-reflective coating. Since refractive index is a fundamental physical property of a substance, it is often used to identify a particular substance, confirm its purity, or measure its concentration. Refractive index is used to measure solids, liquids, and gases. Most commonly it is used to measure the concentration of a solute in an aqueous solution. A refractometer is the instrument used to measure refractive index. For a solution of sugar, the refractive index can be used to determine the sugar content. Several techniques and discussion were reported for the measurement of concentration and temperature dependence of refractive index of liquids. The ordinary method for the measurement of refractive index of a liquid is the measurement of minimum deviation produced by a light beam that pass through the liquid contained in a hollow prism made of glass. The glass is opaque for infrared and ultraviolet radiation which is using we limited with source as visible light.the optical spectrometer suits best for assessment of refractive index of transparent liquid is another generally used instruments for the determination of refractive index of the liquid. This paper reports the variations of refractive index of oil of different concentration. Relatively simple and effective techniques, minimum deviation produced by prism are employed to measuring refractive index of solutions. The results were compared with the results obtained from optical spectrometer. The absolute refractive index of a medium is the ratio of the speed of electromagnetic radiation in free space to the speed of the radiation in that medium. The relative refractive index is the ratio of the speed of light in one medium to that in the adjacent medium. Refraction occurs with all types of waves but is most familiar with light waves. The refractive index of a medium differs with frequency. This effect, known as dispersion, lets a prism divide white light into its constituent spectral colours. For a given colour, the refractive index of a medium depends on the density of the medium.

4 LITERATURE REVIEW This method is the simple and reliable method of measuring the refractive index of oil. In this method, we measure the concentration dependent of refractive index of oil of different sweet house. Several scientists have been done in the different field purpose of the education, to determine the concentration of solutions and also measure the refractive index of the liquid at different temperatures. Refractive index is one of the most important optical properties of a medium. It plays vital role in many areas of material science with special reference to thin film technology and fiber optics. Similarly, measurement of refractive index is widely used in analytical chemistry to determine the concentration of solutions. Recent studies (Schwartz & Berglund, 1999) (Olesberg, Arnold, Hu, & Wiencek, 2000)provide more detailed discussion on the concentration mapping by the measurement of refractive index of liquids. Temperature coefficient of refractive index can also be used to calculate thermal expansion coefficient (Miller, Hussmann, & McLaughlin, 1975). Several techniques are reported in literature for the measurement of concentration dependence of refractive index of liquids (McPherson, et al., 1999). The present project reports a relatively simple and effective technique, which can be used to measure the refractive index of the oil at different concentrations.

$MATERIAL AND METHODS A convenient formula for refractive index, μ can be obtained in the minimum deviation case when a ray of light suffers deviation while passing through a prism.$

5 MATERIAL AND METHODS A convenient formula for refractive index, μ can be obtained in the minimum deviation case when a ray of light suffers deviation while passing through a prism. The deviation produced by the prism depends on the angle of incidence. For a certain value of the angle of incidence, the angle of deviation is minimum. If δm denotes the angle of minimum deviation for a given prism of refractive angle A, then the refractive index of the material of the prism μ is given by, μ = sin [A+δm ] 2... (1) sin ( A 2 ) Equation (1) has been employed to calculate the refractive index of the liquids. Experimental arrangement used in our study is depicted. Specially constructed hollow prism was used to measure the refractive index of oils with the help of an optical spectrometer. A monochromatic source of laser light was used and a collimated beam was allowed to fall on one reflecting face of the liquid prism and the angle of minimum deviation was determined. Mean of two values were taken for each angle of minimum deviation. For the measurement of refractive index of oil of different school canteen poured into the hollow prism and the angle of minimum deviation was measured. (SUBEDI, 2006). We calculate by taking different samples inside the hollow prism and then calculate directly by using spectrometer by minimum deviation method we use the relation (1).

6 RESULTS AND DISCUSSION Effect of Concentration: 1.54 µ µ Sagarmatha Saugat Sagun Gautam Lumbini Fig2: Refractive index of cooking oil in different sweet house in surkhet bazzar. The refractive index of oil as function of concentration is plot in the figure (2). The highest refractive index of the cooking oil of Sagarmatha sweet house is and the lowest refractive index of cooking oil of Lumbini sweet house is The range of the refractive index of soybean oil is 1.46 to The cooking oil of the Sagarmatha sweet house is not suitable to use for cook food. CONCLUSION We have been able to design a hollow prism suitable for the measurement of refractive index of transparent liquids. Experimental results showed that this technique could be safely employed to study the concentration dependence of refractive index of oil on their concentration. It was found that the value is in agreement with the real value of refractive index of soybean oil measured by the other experiment. A linear dependence of refractive index of some solutions with their concentration was observed.

7 Reference McPherson, A., Malkin, A., Kuznetsov, Y., Koszelak, S., Wells, M., Jenkins, G., et al. (1999). Effects of microgravity on protein crystallization: evidence for concentration gradients around growing crystals. J. Crystal Growth, 196. Miller, A., Hussmann, E., & McLaughlin, W. (1975). Interferometer for measuring fast changes of refractive index and temperature in transparent liquids. Review of Scientific instruments, 46, Olesberg, J., Arnold, M., Hu, S.-Y., & Wiencek, J. (2000). Temperature insensitive near infrared method for determination of protein concentration during protein crystal growth. Analytical Chemistry,72, Schwartz, A., & Berglund, K. (1999). The use of Raman spectroscopy for in situ monitoring of lysozyme concentration during crystallization in a hanging drop. J. Crystal Growth, 599. Subedi, D. (2006). Study of tempareture and concentration depencedent of refractive index of liquid using novel technique. Kathmandu University journal of science, engineering and technology, II.

Study of Refractive Index of Potassium Dichromate Solution as a Function of its Concentration

$Study of Refractive Index of Potassium Dichromate Solution as a Function of its Concentration$ Study of Refractive Index of Potassium Dichromate Solution as a Function of its Concentration N.V.Wani 1,S.M. Dongarge 2 andu.v. Biradar 3 1,2,3 Department of Physics, Mahatma Basweshwar Mahavidyalaya,