Prismatic effect (Dispersion of Light by Prisms)

Share This

On a rainy day when the roads are wet and you are driving a car or riding a bike, sometimes you see that the petrol spills on the road. When the petrol mixes with the water we can see stretches of different layers of colours on the road. Why does this happen? What is the phenomenon behind this? Much like stars, galaxies, and the flight of a bumblebee, some complicated physics underlie this beautiful act of nature. For starters, the effect, where light is broken into the visible spectrum of colours, is known as the ‘Dispersion of Light’. Another name for it is the Prismatic Effect, since the effect is the same as if one looked at light through a prism.

With the help of a narrow beam of light, a glass prism, and a white wall it is possible to produce the band of seven colours using white light. Keep this arrangement near the window. Place the glass prism in such a manner that the sunlight through the window falls on one side of the prism and then on the white wall.  Upon passage through the prism, the white light is separated into its component colours – Violet, Indigo, Blue, Green, Yellow, Orange and Red. The separation of visible light into its different colours is known as dispersion. Each colour is characteristic of a distinct wave frequency; and different frequencies of light waves will bend varying amounts upon passage through a prism. Dispersion of prism takes place because white light entering the prism consists of so many different colours. According to Cauchy’s formula, refractive index (μ) of a material depends upon wavelength (λ) and is given by,

 

μ (λ)=A+B/λ2+C/λ4+.....


Where n is the refractive index, λ is the wavelength and A, B, C, ….. are the coefficients coated for λ as the vacuum wavelengths (empirical coefficients).

Since the wavelength of violet light is smaller than of the red light μv > μrtherefore the violet light has a larger angle than the red light. As a result, the dispersion of white light takes place on the second surface of the prism. The pattern of colour which is obtained is called as a spectrum.  Sometimes in the rainbow, you may not see all the seven colours. This is because the colours overlap each other.

 

More blogs



18 AugWhy consider using Google Classrooms with OneNote...

Why consider using Google Classrooms with OneNote  Before introducing G Suite, OneNote Class Notebook was one of the ...

18 AugRole of Ed Tech...

Role of EdTech With the ongoing global pandemic, there is a growing demand for technology-driven education systems. T...

18 AugSocial-emotional challenges faced students...

Social-emotional challenges faced students Going through complicated challenges at certain phases is a part of life for ev...

18 AugRole of Educators in the Post Covid - 19...

Role of Educators in the Post Covid World Covid -19 has become the worst catastrophe faced by this global w...

24 NovChemical Properties of Carbon Compounds...

Carbon compounds can be present in our food, clothing, and even the lead of the pencil we use. It exists in both its free and mixed forms. It can b...

17 NovWhat is bullying?...

What is bullying? Bullying is the usage of force or threat to intermediate or aggressively dominate others. A bully is a p...

18 OctRevisiting Health...

The disruption of the erstwhile 'normal routine' has afforded us a rare opportunity to hold our horses and to reflect ...

30 OctWhat is Practical Knowledge and why it is importan...

Practical knowledge as the name suggests is t...

11 JanHow to speak English fluently?...

If you can speak you can influence, If you can influence you can change lives’ English, being the Universal language, plays a cru...

https://www.gurukulglobal.com/assets/uploads/Partners_Logos/brand1.png
https://www.gurukulglobal.com/assets/uploads/Partners_Logos/brand2.png
https://www.gurukulglobal.com/assets/uploads/Partners_Logos/isa.png
https://www.gurukulglobal.com/assets/uploads/Partners_Logos/NSS.png
https://www.gurukulglobal.com/assets/uploads/Partners_Logos/atl.png
https://www.gurukulglobal.com/assets/uploads/Partners_Logos/cbse.png

Affiliations and Recognitions

Bulletin Board

View More