Question

The refractive index of glass is 1.5. What does it mean?

Answer 1

Refractive index

1. It is defined as the ratio of the speed of light in a vacuum to the ratio of the speed of light in a specific medium. It is denoted by n with $n=\frac{c}{v}$.
2. The above statement means that the speed of light in glass is 1.5 times slower than the speed of light in a vacuum.
3. It also means that the speed of light in glass is $\frac{1}{1.5}$ times the speed of light in air.