Velocity of light in transparent medium is `2 xx 10^8` m/sec. Calculate the refractive index.

Velocity oflight through a mediumis 1.5 x 10^8 m/sec . Then find the R.I. of that medium.

Fill in the blank spaces with appropriate answers: The critical angle of light that incidents inside the denser medium is 30^@ . Then the refractive index of the material is __________.