A ray in oil (n = 1.52) reaches a boundary with water (n = 1.33) at 55.9 deg. Does it reflect internally or refract into the air?

Ray reflects internally

Explanation:

Given:

Ray in oil (n1) = 1.52

Ray in water (n2) = 1.33

θ = 55.9°

Computation:

Step 1. Find critical angel (θc)

Sinθc/Sin90° = Ray in water / Ray in oil

Sinθc/1 = 1.33/1.52

θc = 61°

Since, θ = 55.9° is smaller than θc = 61°

So, Ray reflects internally.