If the speed of light in a vacuum is 1.2 times that of the speed of light in a

given material, what is the index of refraction for that material?

Write your answer as a decimal.

Refractive index if denoted by n is different for different materials.

Let, the speed of light in vacuum = v₁ = 3x10⁸m/s

refractive index of vacuum = n₁ = 1

refractive index of second medium = n₂ = 1.2

now according to Snell's law

n₁ / n₂ = v₂ / v₁

thus the speed of light in second medium with refractive index 1.2 will be

v₂ = v₁ (n₁ / n₂) = 3x 10⁸m/s (1/1.2) = 2.5x10⁸ m/s

Refractive Index for the material is 1.2

Explanation:

Formula for Refractive index of the material (n) = speed of light in vacuum/speed of light in the material Given detail is speed of light in vacuum = 1.2 (speed of light in the material)

⇒ Speed of light in vacuum/Speed of light in the material

= 1.2 = n

The refractive index and the index of refraction are same. It describes how light travels through a substance.