# When the incidence angle is equal to the angle of refraction

## Homework Statement

When the incidence angle is equal to the angle of refraction?

sina/sinb=n2/n1

## The Attempt at a Solution

I think as a=b => sina=sinb => n1=n2. We should have the same environment? But is that refraction?

blue_leaf77
Homework Helper
At the interface of two different media, there is a certain angle of incidence where the incident ray just passes straight through. What is this angle?

At the interface of two different media, there is a certain angle of incidence where the incident ray just passes straight through. What is this angle?
when b= pi/2 rad. It is the limit angle for a. sina=n2/n1

blue_leaf77
Homework Helper
when b= pi/2 rad. It is the limit angle for a. sina=n2/n1
No, that corresponds to critical angle refraction. It very simple, you have Snell's law ##n_1 \sin a = n_2 \sin b##. Try to find a trivial angle ##a=b## which will make the left and right hand side of Snell's law equal irrespective of the refractive indices.

No, that corresponds to critical angle refraction. It very simple, you have Snell's law ##n_1 \sin a = n_2 \sin b##. Try to find a trivial angle ##a=b## which will make the left and right hand side of Snell's law equal irrespective of the refractive indices.
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