Question

What is the critical angle c for total internal reflection if the material is clear acrylic, with a refractive index of 1.5?

Answer 1

Refractive index is related by the formula:
n = sin(∅₂) / sin(∅₁)
Here, ∅₂ = 90° in the case of total internal reflection.
1.5 = 1/sin(∅₁)
∅₁ = 41.8°