- #1

shakeysg

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## Homework Statement

figure shows a 90 degrees triangular prism of refractive index n whereby light enters at point A with an incident angle of θ. The light then refracts at point B with an angle of refraction of 90 degrees.

determine index of refraction, n in terms of θ. refer to figure attached.

## Homework Equations

using snell's law of refraction,

n.sinθ=n

_{1}.sinθ

_{1}

## The Attempt at a Solution

first I used an snell's law to get an eqn

1.sinθ=n.sinθ

_{1}----------------------(1)

using properties of angles and triangles I got

θ

_{2}, θ

_{3}and θ

_{4}.

θ1=θ3, θ2=θ4.

using snell's law again I got

n.sinθ4=1.sin 90 degrees

n.sinθ4=1

I tried using trigonometry to compute the thetas together and eventually eliminate θ1. But I was not able to do so. Am I missing something?

Since I got stuck, I thought if θ1=45 degrees, getting n in terms of θ is not a problem. But I reasoned to myself that it cannot be possible as I do not know θ4 and n. So making an assumption is not right. I think? I could be wrong though.. hmm..

help would be greatly appreciated and I am sorry if posted anything wrongly such as the format or thought process since this is the first time I am posting.

Thanks!

Syeh