The refractive index of diamond is 2.42. What is the meaning of this statement?

Q.  The refractive index of diamond is 2.42. What is the meaning of this statement?

 

Answer:-

The diamond with refractive index of 2.42, is the most ‘optically denser medium’ and there for the speed of light in diamond will be less i.e. 1.23 × 108ms−1 (= 3 × 108 ms−1/2.42 ) compare to speed of light in vacuum C = 3 × 108 m s– 1