Question

Refractive indices of four media A, B, C and D are given below:  

Medium	Refractive index
A	1.33
B	1.44
C	1.52
D	1.65

In which of these four media is the speed of light (i) maximum, and (ii) minimum?

Answer 1

 The refractive index of a medium is related to the speed of light as follows:  

 Refractive index =`"speed of light in vacuum "/"speed of light in a medium"`  

Since the speed of light in vacuum is a constant, the refractive index becomes inversely proportional to the speed of light in a medium. 

   (1)The speed of light is maximum in a medium that has the lowest refractive index, ie., medium A  

 (2) The speed of light is minimum in a medium that has the highest refractive index, ie., medium  D.