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

Tags:
1. May 19, 2016

1. The problem statement, all variables and given/known data
When the incidence angle is equal to the angle of refraction?

2. Relevant equations
sina/sinb=n2/n1

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

2. May 19, 2016

### blue_leaf77

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?

3. May 19, 2016

when b= pi/2 rad. It is the limit angle for a. sina=n2/n1

4. May 19, 2016

### blue_leaf77

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.

5. May 19, 2016