Total Internal Reflection and Critical Angles

Question 1

When going from high to low refractive index, what can happen in regards to the critical angle

Answer 1

As we know that the emergent ray will bend away from the normal (r > i), when we increase i, so will r. There is a point at which when we have increased the angle of incidence enough that the angle of refraction will be at a 90 degrees to the normal. The angle i in this situation is the critical angle.

Question 2

What happens when we go beyond the critical angle

Answer 2

Going beyond the critical angle will result in total internal reflection. A phenomenon in which the ray incident ray is reflected back in the medium. As reflection is occurring that means the angle of incidence = angle of reflection

Question 3

How to calculate critical angle

Answer 3

C = sin-1(1/n)