Question

If the refractive index of a certain material is 2.5, the speed of light in this material is ​

Answer 1

The refractive index of a material is related to the speed of the light by the relation⇒

refractive index of a material = (speed of light in vacuum)/(speed of light in the material)

In the given question,

The  refractive index of a material (R.I.) = 2.5

The speed of light in vacuum( c) = 3 ×10 ⁸ m/s

The speed of light in the material = (c)/ (R.I.)

                                                       = 1.2×10 ⁸ m/s

Hence, the speed of light in the material =1.2×10 ⁸ m/s.