Finding the Critical Angle of Glass in Water

AI Thread Summary
The critical angle for glass in air is 44 degrees, and the question asks for the critical angle when the glass is immersed in water. The relevant equation is sin(critical angle) = 1/index of refraction, with air's index at 1.00 and water's at 1.333. To find the critical angle in water, the equation n1sinQ = n2sinQ can be applied, where n1 is the refractive index of glass and n2 is that of water. The textbook solution indicates that the critical angle in water is 68 degrees.
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Homework Statement


The critical angle for a special glass in air is 44 degrees. What is the critical angle if the glass is immersed in water?


Homework Equations


sin(critical angle) = 1/index of refraction

index of refraction of air is 1.00
index of refraction of water is 1.333

The Attempt at a Solution


I have no clue where to start that's the problem :S.

Just for reference, the textbook answer is 68 degrees.

Thanks.
 
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qszwdxefc said:
sin(critical angle) = 1/index of refraction
Hint: That's only true if the surrounding medium has n = 1. (How is the critical angle formula derived?)
 
Ah, Snell's Law where \theta_2 = 90^\circ.

Thanks.
 
Last edited:
Have you tried using the eqaution n1sinQ=n2sinQ
by the way the one is just saying its the first refractive index, and the Q is theta.
Maybe you could try this eqaution.
Thanks I hope that helps... :cool:

qszwdxefc said:

Homework Statement


The critical angle for a special glass in air is 44 degrees. What is the critical angle if the glass is immersed in water?


Homework Equations


sin(critical angle) = 1/index of refraction

index of refraction of air is 1.00
index of refraction of water is 1.333

The Attempt at a Solution


I have no clue where to start that's the problem :S.

Just for reference, the textbook answer is 68 degrees.

Thanks.
 

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