Latest Questions UpdateCategory: QuestionsRefraction Through Prism in Different Medium
Kirti Sharma Staff asked 6 months ago
What is Refraction? How the Refraction through the prism in Different mediums will be explained deeply.
2 Answers
Dr. Mukesh Shrimali Staff answered 6 months ago
The phenomenon in which there is a change in the speed of light as it travels from one medium to another and consequent bending of a ray of light incident obliquely at the surface of separation of the 2 media is known as refraction of light. If you observe a pencil in a glass of water, it will appear to be bent or displaced due to the effect of refraction.


Laws of Refraction
The incident ray, the refracted ray and the normal all lie in the same plane. For two particular media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant N. Use the formula to calculate the angle of refraction is

n = sin i / sin r  (Snell’s Law)

Some Applications of refraction are 

  • Apparent depth:
    • Apparent depth is always less than the real depth due to refraction of light. A water tank or a fish appears less deep than its actual depth due to Refraction.
  • Refraction effect of sunset and sunrise :
    • The sun is visible to us before actual sun rise and after actual sunset. This is because of Atmospheric Refraction of Light.
Anik answered 6 months ago

The main reason for refraction of light is due to the reason that when light travels from one medium to another the velocity of the light wave changes due to change in wavelength of light wave. So since velocity of the light is not same in every medium the path of light changes .

For example, when light travels from air into water, it slows down, causing it to change direction slightly. This change of direction is called refraction. When light enters a more dense substance (higher refractive index), it ‘bends’ more towards the normal line.

The amount of bending depends on two things:

  1. Change in speed – if a substance causes the light to speed up or slow down more, it will refract (bend) more.
  2. Angle of the incident ray – if the light is entering the substance at a greater angle, the amount of refraction will also be more noticeable. On the other hand, if the light is entering the new substance from straight on (at 90° to the surface), the light will still slow down, but it won’t change direction at all.

If light enters any substance with a higher refractive index (such as from air into glass) it slows down. The light bends towards the normal line.

If light travels enters into a substance with a lower refractive index (such as from water into air) it speeds up. The light bends away from the normal line.

A higher refractive index shows that light will slow down and change direction more as it enters the substance.