Proving Snell's Law with Fermat's Principle: A Beginner's Guide

In summary, the conversation discusses using Fermat's principle to prove Snell's Law, with suggestions to write out expressions for sines of relevant angles and apply Fermat's principle. The conversation also mentions using algebra and expressing velocities in terms of indexes of refraction.
  • #1
MissP.25_5
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Can someone help me on how to prove Snell's Law using Fermat's principle? I'm not so good with topics about light, so I don't how to start.
 

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MissP.25_5 said:
Can someone help me on how to prove Snell's Law using Fermat's principle? I'm not so good with topics about light, so I don't how to start.

Looks like you've made a start...

It also looks like you might want to write out expressions for sines of the relevant angles in terms of the variables you're using so that you'll be able to recognize them later. Then apply Fermat's principle to the time expression you've written. After that it'll be a lot of banging away at the algebra in order to pattern-match the sine expressions...

Remember to express your velocities c1 and c2 in terms of the indexes of refraction.
 
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I got it! Thanks :)
 

FAQ: Proving Snell's Law with Fermat's Principle: A Beginner's Guide

What is Snell's Law and why is it important?

Snell's Law is a fundamental principle in optics that describes the relationship between the angles of incidence and refraction at the interface between two different materials. It is important because it helps us understand how light behaves as it passes through different mediums, and it has many practical applications in fields such as engineering, medicine, and astronomy.

What is Fermat's Principle and how does it relate to Snell's Law?

Fermat's Principle is a principle of least time, which states that light will always take the path that requires the least amount of time to travel from one point to another. Snell's Law is a direct consequence of Fermat's Principle, as it shows that the path of light through different mediums is the one that minimizes the time it takes to travel between two points.

What is the process for proving Snell's Law using Fermat's Principle?

The process involves setting up a mathematical expression for the time it takes for light to travel through two different mediums, and then using calculus to minimize this expression. This results in an equation that is equivalent to Snell's Law, providing a rigorous proof of the principle.

Can Snell's Law be extended to three dimensions?

Yes, Snell's Law can be extended to three dimensions and is known as the three-dimensional Snell's Law. It describes the relationship between the angles of incidence and refraction in a three-dimensional space, taking into account the direction of light propagation.

What are some real-world applications of Snell's Law and Fermat's Principle?

Snell's Law and Fermat's Principle have many practical applications, including the design of lenses and mirrors in optics, the study of light refraction in the atmosphere, and the development of medical imaging techniques such as MRI and ultrasound. They are also used in the design of optical devices such as cameras, telescopes, and microscopes.

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