If the speed of light through material Z is

2.5×108 m/s, what is this material’s index of
refraction? The speed of light in a vacuum is
3 × 108 m/s.

I = 3*10^8 / 2.5*10^8 = 1.2.

To determine the index of refraction of material Z, we can use the formula:

Index of Refraction (n) = Speed of Light in Vacuum / Speed of Light in Material

Given that the speed of light in a vacuum is 3 × 10^8 m/s (represented as c) and the speed of light in material Z is 2.5 × 10^8 m/s (represented as v), we can substitute the values into the formula:

n = c / v
= (3 × 10^8 m/s) / (2.5 × 10^8 m/s)
= 1.2

Therefore, the index of refraction of material Z is 1.2.