Question

The refractive index of ruby is 1.71. what is meant by this statement

Answer 1

1. The Refractive index of a medium is defined as the ratio of the speed of light in a vacuum to that in the medium. It is a dimensionless quantity that describes how light travels in the medium.
2. Refractive index = $\frac{Speedoflightinvacuum}{Speedoflightinthemedium}$
3. Refractive index of the ruby is 1.71 which means that the speed of light in ruby is $\frac{1}{1.7}$ times the speed of light in a vacuum.