# AS refraction helpWatch

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#1
can pls explain how to find the critical angle even though you only know the RI of one of the materials?

the question is 2c): https://pmt.physicsandmathstutor.com...Refraction.pdf
0
3 months ago
#2
Consider the refractive index of air as 1

(Original post by Soul Wavel3ngth)can pls explain how to finder the critical angle even though you only know the RI of one of the materials?

0
3 months ago
#3
Total internal reflection is when the light passing from a more dense medium is refracted by 90 degrees when it passes into a less dense medium (in this case from water to glass).

Total internal reflection takes place when the angle of incidence is greater than the critical angle.

What you have to do is calculate the critical angle, use your answer from 2b to get the angle of incidence, and compare them to prove that the statement in 2c is true.
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