• Support PF! Buy your school textbooks, materials and every day products Here!

Critical Angle Problem

  • Thread starter qszwdxefc
  • Start date
  • #1
10
0

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.
 

Answers and Replies

  • #2
Doc Al
Mentor
44,882
1,129
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?)
 
  • #3
10
0
Ah, Snell's Law where [tex]\theta_2[/tex] = [tex]90^\circ[/tex].

Thanks.
 
Last edited:
  • #4
77
0
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:

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.
 

Related Threads for: Critical Angle Problem

  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
2
Views
2K
Replies
1
Views
683
  • Last Post
Replies
2
Views
3K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
2
Views
837
Top