Question

Refractive indices of media A,B,C and D are A - 1.25 B - 1.45 C - 1.33 D - 1.50 In which of the four media the speed of light is maximum and minimum ?

Answer 1

First of all, let's define refractive index :

Absolute Refractive Index of any medium is defined as the ratio of velocity of light in vacuum to the velocity of light in that particular medium.

$\mu = \dfrac{vel. \: in \: vacuum}{vel. \: in \: medium}$

Since , velocity of light in vacuum is constant we can say that :

$\boxed{ \red{ \bold{ \mu \propto \: \dfrac{1}{vel. \: in \: medium} }}}$

So higher the refractive index of any medium , lower will be the velocity of light in that medium and vice versa.

Among the medium A , B , C , D :

Maximum velocity will be in A , because of lowest Refractive Index.

Minimum velocity will be in D , because of highest Refractive Index.

Answer 2

Given ,

A refractive index in medium A , B , C and D are 1.25 , 1.45 , 1.33 and 1.50

As we know that ,

Refractive index of a medium is defined as the ratio of velocity of light in vacuum to the velocity of light in medium

$\large \mathtt{ \fbox{Refractive \: index = \frac{Velocity \: of \: light \: in \: vacuum }{Velocity \: of \: light \: in \: medium} }}$

It has no units and dimensions

A high refractive index of a medium indicates that the light travels slowly through that medium

Thus ,

The velocity of light is maximum in medium A and minimum in medium D

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