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

Refractive index of water is 1.33' - What if the meaning of the statement?

The value of refractive index of diamond is

The refractive index of water is 4/3'. Explain the meaning of this statement.

The value of refractive index of diamond

A ray of laser of a wavelength 630 nm is incident at an angle of 30^(@) at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is 2.42 and that of air is 1. Choose the correct option