Why light bends in water

As you mentioned, the energy of a red light beam is divided amongst many photons, whereas the energy of a violet light beam is more concentrated among fewer photons. It's comprehensive and detailed explanation was given by Fermat. Which in turn gives the explanation for Snell's law. His idea is this: that out of all possible paths that it might take to get from one point to another, light takes the path which requires the shortest time.

Before we continue any further we must, however, make an assumption about the speed of light in water. So without previous knowledge about the wave nature of light Fermat's Principle can explain most phenomena in geometric optics.

I came to know that red light has the longest wavelength and then I read a formula, Energy is inversely proportional to wavelength. That means that red light contains the least energy. And it bends the least.

Why does it not bend as much as violet I know they have more energy but what makes them bend? A crystal is a many body organized quantum mechanical entity. Even though composed by zillions of atoms, it can be treated quantum mechanically as one entity when scattering happens, a photon hitting a crystal. The quantum mechanical solution will give a probability distribution for the scattering of a single photon to get through the crystal.

This probability distribution has a sharp maximum at the dispersion angle of the crystal. This is BECAUSE the classical framework emerges from the underlying quantum mechanical, has to be consistent and it can be shown to be. The difference in the energy of the photon makes a difference in the maximum of the scattering angle because the energy enters scattering equations. To answer this question first you need to understand what prisms are made of, usually glass, that is silica SiO2.

Now this size is very small compared to visible light photons' wavelength which is about nm. When the photon's wavelength is much bigger then the atom's size they interact with, the interaction can be described and in the case of glass is best described by elastic scattering Rayleigh , by the way this is the reason why the sky is blue.

Now this causes the photons with shorter wavelength to interact with the atoms more higher probability , causing the angle to change more in the case of shorter wavelength. Just like the sky is blue, that is, the shorter wavelength photons get scattered more higher probability , and change angle more into our eyes to make the sky look blue, analogously the shorter wavelength photons will interact with the atoms in the prism more and scatter more and change angle more.

As you say, the red light photons contains the least energy, have the longest wavelength in the visible range , and interact with the atoms the least, thus, they follow an almost straight path through the prism. Sign up to join this community. The best answers are voted up and rise to the top.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why does light bend? Ask Question. Asked 6 years, 1 month ago. Active 1 year, 2 months ago. Viewed 8k times. Please don't use Snell's law in your answer. Improve this question. Aryan Beezadhur 12 12 bronze badges. Aaryan Dewan Aaryan Dewan 1, 3 3 gold badges 16 16 silver badges 35 35 bronze badges.

You know the boundary conditions for a linear wave i. This is another way of saying that one needs an integer number of wavelengths between two boundaries. If the boundaries happen to be a triangular prism then different wavelengths must connect to different points on the two surfaces to ensure a continuous wave function and first derivative The boundary conditions are another way of saying that boundary itself assumed to be infinitely thin cannot contain localized sources e.

Add a comment. Active Oldest Votes. Improve this answer. But the diagram and didactic and mental representation are not the same using the wave form or the ray form. This is pretty classic in physics that you can watch a same phenomena under 2 or 3 very different facets I would say it's one of the best beauty of physics understanding. Claiming they are two didactic different ways to achieve the same result is hiding where they come from, in my opinion.

In most optic-based explanations you see rays and tilt angles, and no more. I do agree that the wave explanation is more constructive. Yet, you'll have to explain why celerity and wavelength change, but it's doable at least for university students in sciences, not for pupils or litterature students The refractive index of red light in glass is 1.

The refractive index of violet light is 1. This slight difference is enough for the shorter wavelengths of light to be refracted more.

A rainbow is caused because each colour refracts at slightly different angles as it enters, reflects off the inside and then leaves each tiny drop of rain. A rainbow is easy to create using a spray bottle and the sunshine. The centre of the circle of the rainbow will always be the shadow of your head on the ground. The secondary rainbow that can sometimes be seen is caused by each ray of light reflecting twice on the inside of each droplet before it leaves.

This second reflection causes the colours on the secondary rainbow to be reversed. Red is at the top for the primary rainbow, but in the secondary rainbow, red is at the bottom. Learn more about the many different kinds of rainbows and how they are formed from the Atoptics website — Rainbows reflect and Rainbow orders. Learn more about human lenses, optics, photoreceptors and neural pathways that enable vision through this tutorial from Biology Online.

Add to collection. Activity ideas Use these activities with your students to explore refration further: Investigating refraction and spearfishing — students aim spears at a model of a fish in a container of water. When they move their spears towards the fish, they miss! Angle of refraction calculator challenge — students choose two types of transparent substance. They then enter the angle of the incident ray in the spreadsheet calculator, and the angle of the refracted ray is calculated for them.

Light and sight: true or false? This activity can be done individually, in pairs or as a whole class. Useful links Learn more about the many different kinds of rainbows and how they are formed from the Atoptics website — Rainbows reflect and Rainbow orders. Go to full glossary Add 0 items to collection. Download 0 items. Twitter Pinterest Facebook Instagram.

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