Determine the refractive index of turpentine and the speed of propagation of light in turpentine

Determine the refractive index of turpentine and the speed of propagation of light in turpentine if it is known that at an angle of incidence of 45 °, the angle of refraction is 30 °

From Snell’s law, the angle of incidence of light on a surface is related to the angle of refraction by the ratio:
n1 * sinα = n2 * sinβ.
sinα / sinβ = n2 / n1, where n2 / n1 = n21 is the refractive index of the two media, α = 45º, β = 30º.
n21 = sinα / sinβ = sin45º / sin30º = 1.41.
The refractive index is also equal to:
n21 = C / V, C is the speed of light (C = 3 * 10 ^ 8 m / s), V is the speed of light in turpentine.
V = C / n21 = (3 * 10 ^ 8) / 1.41 = 2.13 * 10 ^ 8 m / s.
Answer: The refractive index is 1.41, the speed of propagation of light in turpentine is 2.13 * 10 ^ 8 m / s.