Question

What is refraction of light? How is it related to the refractive index?

Answer 1

Hint: Refraction and refractive index are related to each other as refraction occurs due to refractive index of any medium or object from which the light passes. Using this fact, we will solve the question and find the relation.

Formula used: $\dfrac{\sin {{\theta }_{1}}}{\sin {{\theta }_{2}}}=\dfrac{{{v}_{1}}}{{{v}_{2}}}=\dfrac{{{n}_{2}}}{{{n}_{1}}}={{n}_{21}}$

Complete step by step answer:
In question we are asked what is refraction of light and how it is related to refractive index. So, first of all we will define the refraction of light.
Refraction of light: When light passes from one medium and enters another medium then the ray of light either comes near to the normal or it goes away from it this phenomenon is called refraction.
Now, when light goes from rarer to denser medium it goes towards the normal and when the light goes from denser to rarer medium it goes away from the normal. Which can be seen from the figures below.

Now, when light bends it makes an angle with respect to the normal and the relation between angle made and refractive index can be shown as,
$\dfrac{\sin {{\theta }_{1}}}{\sin {{\theta }_{2}}}=\dfrac{{{v}_{1}}}{{{v}_{2}}}=\dfrac{{{n}_{2}}}{{{n}_{1}}}={{n}_{21}}$
Where, $\sin {{\theta }_{1}}$ is angle made by the light when it is entering in one medium from another medium,
$\sin {{\theta }_{2}}$ is an angle made by the light when it is leaving the medium it has entered.
${{v}_{1}}$ and ${{v}_{2}}$ are velocities of light in medium 1 and medium 2 respectively.
${{n}_{1}}$and ${{n}_{2}}$ are refractive indexes of medium 1 and medium 2 respectively.
Thus, it can be said that refraction of light occurs due to refractive index of any medium so they both are related to each other.

Note: The alternative definition of refraction of light is that the velocity of light changes when it passes from one medium to another medium. The students must not get confused with the concepts of ray of light going near to normal or away from the normal and they should clear all the concepts before solving the problems.