# Snell's Law, indices of refraction

• monke
In summary, the question asks for the angle of a beam of light that passes through a stack of four transparent materials with different indices of refraction, after entering at a 60 degree angle. The solution involves using Snell's Law and applying it to each layer of the stack. The resulting angle of the beam will be the same as the angle at which it entered, as long as the block has parallel sides.
monke

## Homework Statement

A beam of light in air is incident on a stack of 4 flat transparent materials with indicies of refraction 1.20, 1.40, 1.32, and 1.28. If the angle of incidence for the beam on the first of the four materials is 60*, what angle does the beam make witht the normal when it emerges into the air after passing through the entire stack?

## Homework Equations

what is the best way to start and understand this type of problem?

## The Attempt at a Solution

Do I just use Snell"s Law and use the incides of refraction of air for n sub i and 60 for theta sub i?

A good exercise in this question is to use this version of snell's law:
n1Sinθ1 = n2Sinθ2 and apply this as you work through each layer.
You will get an answer that may surprise you.
Once you get this answer it will reveal something about light entering and leaving parallel sided blocks.

Last edited:
okay what do i use for the n1 sinθ1? is that 60* and the n for air =1.000?

then do i just add all the thetas together?

oh i think i got it you use n=1.00 sin60= 1.20sin theta 1 and then solve for theta 1 and sub in all down the layers until you use n=1.00 and solve for theta i. the angle is the same going out of the layers as it was going in?

That is it.
If the block has parallel sides the light emerges at the same angle it entered.

That is it.
If the block has parallel sides the light emerges at the same angle it entered.

## What is Snell's Law?

Snell's Law, also known as the law of refraction, is a formula that describes the relationship between the angle of incidence and the angle of refraction when a light ray passes through a boundary between two different media.

## How is Snell's Law calculated?

Snell's Law is calculated using the formula: n1sinθ1 = n2sinθ2, where n1 and n2 are the refractive indices of the two media and θ1 and θ2 are the angles of incidence and refraction, respectively.

## What are indices of refraction?

Indices of refraction, also known as refractive indices, are a measure of how much a material can bend light. It is the ratio of the speed of light in a vacuum to the speed of light in the material.

## What factors affect the index of refraction?

The index of refraction is affected by the density and composition of the material. Generally, materials with higher densities and higher optical density have higher indices of refraction.

## Why is Snell's Law important?

Snell's Law is important because it helps us understand how light behaves when it passes through different materials, allowing us to make accurate predictions about the path of light rays. It is also crucial in the development of technologies such as lenses and prisms.

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