Answer:
θ = 50.6
Explanation:
This is a refraction exercise, which is described by the equations
n₁ sin θ₁ = n₂ sin θ₂
where in index 1 we will use it for the incident ray and subscript 2 for the refracted ray
The refractive index of water is tabulated and is n = 1.33, let's calculate the refractive index of the glass
n₁ = n₂ sin θ₂ /sin θ₁
n₁ = 1.33 sin 49.8 /sin 36.2
n₁ = 1.72
With the values of the two refractive indices we can calculate the angle for the total internal reflection
sin θ = n₂ / n₁
θ = sin⁻¹ (n₂ / n₁)
θ = sin⁻¹ (1.33 / 1.72)
θ = 50.6
