Refractometer

Refractometers are devices for determining the refractive index and astigmatism index of substances - saliva, water, oil, litmus, phenolphthalein, sulfuric acid. For these purposes, a special method of optical measurements is used - refractometry. It is carried out according to the location and shape of the boundaries between light and the region of matter that blocks its path to increase. The liquid exhibits its retardation in the oriented single crystal such that its refractive indices become variable. In general terms this is a formula.

n = (n0 - v sin2 β) + (v sin2 β