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. Refractometers are used in chemical analysis to determine the concentration of solutions and their indices to identify the substances present to them. The speed of light in vacuum is a universal constant, but when light travels through a medium its speed slow down as it gets constantly absorbed and re-emitted by the atoms in the material. The absolute refractive index of a medium is the speed of light in a vacuum to the speed of light in that medium. The relative refractive index is the ratio of the speed of light in one medium to that in the adjacent medium. Several techniques are reported in literature for the measurement of concentration in liquids (McPherson 1999, Garcia 1999, Otalora, 1994). The present paper reports a relatively simple and effective technique, which can be used to measure the effect of sugar concentration on the refractive index of water.
Refraction occurs with all types of waves but is most familiar with light waves. When a ray of light travels from one medium to another of different density, its direction is abruptly changed at the surface separating the two media. Refraction depends on the medium. When a ray of light passes from air to glass which means its medium is changing, it is coming from rarer medium to a denser medium, it bends towards the normal drawn at the point of incidence. In this case angle of incidence is greater than angle of refraction. If light passes from glass to air this means from denser to rarer medium the angle of refraction is greater now than angle of incidence