Critical Angle = what ratio is indexes of refraction supposed to be?

[SuperSaiyan3]

So i was doing the Kaplan topical for Lenses and Optics today.

The last question was in regards to the light going from medium 1 to medium 2, where the index of refraction of medium 1 was GREATER than that of 2.

They were asking for the formula.

The answer was sin theta (critical) = n2 / n1

So I get this. But I am wondering what the formula would be if...

- the light was going from medium 1 to medium 2
- BUT the index of refraction of medium TWO was greater than that of 1

Would the formula then be sin theta (critical) = n1 / n2?

I am confused because my High School Physics notes stated that the formula designating critical angle is the ratio of the index of refraction for the medium that produces a SMALLER angle to that of a LARGER angle (like it gets refracted away from the normal). But I think I got this part wrong. I think it was supposed to be the opposite.

CLARIFICATIONS PLEASE!!!!!!!!!!!!!!!!!

SS3

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[crazybob]

http://en.wikipedia.org/wiki/Total_internal_reflection

 

[SuperSaiyan3]

thanks. Great article. Didn't know wikipedia could be this helpful. Answered all my questions! Awesome.