Question

Q4. What is the speed of light in a block of glass that has an Index of refraction of 1.11?

Answer 1

Refractive index(n)= speed of light in vacuum/ speed of light in medium.
Since refractive index is 1.11, and usually we know that the speed of light is 300,000km/s, simply divide 300,000km/s over 1.11. That is, 270,270.2703 when simply rounding, its 270,270 km/s.