# How to find the refractive index of light if the angle of incidence and the angle of refraction are given

**How to find the refractive index of light if the angle of incidence and the angle of refraction are given, for example, such a problem: the angle of incidence of light on the surface of mica is 60 degrees, the angle of refraction is 30 degrees, which is equal to the refractive index of mica.**

According to the law of refraction of light, the ratio of sin of the angle of incidence 60 / to sin of the angle of refraction 30 = n is the refractive index of the second medium relative to the first.

Formula n1 * sin (angle of incidence) = n2 * sin (angle of refraction), where n1 and n2, respectively, are the absolute refractive indices of the first and second media.

The ratio of the sin of the angle of incidence / to the sin of the angle of refraction = n2 / n1 = n is the refractive index of the second medium relative to the first, in our example n2 = the refractive index of mica, but since n air = 1, then n2 / 1 = n2 = n.