Question

relative refractive index n21​

Answer 1

Answer:Suppose n1 be the refractive index of medium 1 and n2 be the refractive index of medium 2

Then the refractive index of medium 1 with respect to medium 2  is

n12 = n1 / n2

and the refractive index of medium 2 with respect to medium 1 will be

n21 = n2 / n1

And the relation between the above two is

n12 = 1 /n21

Hope this helps.

Explanation:

Answer 2

Answer:

The relative refractive index between the two media is  $n_{21}=\frac{n_{2}}{n_{1}}$.

Explanation:

The refractive index is defined as the ratio of the speed of light in  vacuum(c) to the speed of the light in the medium(v).

$n=\frac{c}{v}$

Refractive index gives the measure of slowness of light in medium with respect to the speed of light through vacuum, which is a constant.

To compare the value of the refractive indices of two different media, let  us consider $n_{1}$ and $n_{2}$ be the refractive indices of medium 1 and 2 respectively.

Then the refractive index of medium 1 is given by

$n_{1} =\frac{c}{v_{1} }$

and of medium 2,  $n_{2} =\frac{c}{v_{2} }$

The relative refractive index between the two media is written as $n_{21}$, which says the refractive index of medium 1 with respect to medium 2.

In other words, it is the velocity of light in medium 1 with respect to the velocity of light in medium 2.

Hence, $n_{21}=\frac{{v_{1}}}{ v_{2}}$

$=\frac{\frac{c}{n_{1}} }{\frac{c}{n_{2}} }=\frac{c}{n_{1}} \times \frac{n_{2}}{c}=\frac{n_{2}}{n_{1}}$

Therefore, the relative refractive index between the media is $n_{21}=\frac{n_{2}}{n_{1}}$.