Application of He-Ne Laser to Study of the Variation of Refractive Index of Liquid Solutions with the Concentration

Vivek Kumar Singh, Brij Bir Singh Jaswal, Vinay Kumar, Ram Prakash, Priyanka Rai


In the present paper, we have presented the variation of the refractive index of liquid solutions with the concentration at the He-Ne laser wavelength 632.8 nm. The measurements of the present experiment were carried out using the conventional minimum deviation method of an equilateral hollow glass prism. We measured the refractive indices of sugar solutions, sodium chloride (NaCl) solutions, and sodium (Na) for a range of density varying from distilled water to a saturated condition and their variation with the concentration is presented. Our results reveal that the refractive index of liquid solutions varies linearly with the concentration of sugar and sodium chloride at low concentrations. For the higher concentrations of sugar solution we found a slight curvature from the plot of refractive index vs concentration of solution. For the quantitative measurements of sugar, NaCl and Na present in different kinds of samples we drew the calibration curves. We have verified our results with the results reported and obtained from atomic absorption spectroscopy (AAS). We have also used this method to determine the salinity of the water sample of Adriatic Sea.

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