Question

What causes the refraction of light ?

Answer 1

Hint: In order to answer the above question, we will be studying the phenomenon of refraction of light. We will study about the cause of refraction. We will also be studying the factors which play a vital role in refraction and the amount of bending of light.

Complete answer:
The bending of light (as well as sound, water, and other waves) as it moves through one transparent material into another is known as refraction. Lenses, magnifying glasses, prisms, and rainbows are all possible because of this bending by refraction. Even our eyes are reliant on light bending. We wouldn't be able to concentrate light through our retina without refraction.

As we all know, when light passes at an angle through a material with a particular refractive index, it refracts (optical density). A change in speed causes this change in direction. As light travels from air to water, for example, it slows down and continues to travel at an angle or in a different direction.

The amount of bending is determined by two factors:
Change in speed: a material that allows light to refract (bend) more can cause it to speed up or slow down more.
Angle of the incident ray: the amount of refraction would be more significant if the light enters the material at a greater angle. On the other side, if light enters the new material from the front (at $90$ degrees to the surface), the light will slow down but not change direction.

All angles are calculated using a $90$-degree imaginary line drawn on the surface of the two substances.
-As light passes through a material with a higher refractive index than air (such as glass), it slows down. The light bends in the direction of the normal line.
-As light reaches a material with a lower refractive index (for example, from glass to air), it accelerates. The light deviates from the normal line.
-When light reaches a material with a higher refractive index, it can slow down and change direction more.
It can be concluded from the above answer that the main cause of refraction is the change in the speed of light due to the changing density of the material.

Note:It is very important to note that the refraction of light plays a very vital role in almost all the optical instruments as the main key part of any optical instrument is the lens. The phenomena of dispersion, i.e., the splitting of white light into seven colours, which causes the rainbow is caused due to the refraction of light.