A Ray of Light in Water (Index N₁) Is Incident

Multiple Choice

A ray of light in water (index n₁) is incident on its surface (with air) at the critical angle. Some oil (index n₂) is now floated on the water. The angle between the ray in the oil and the normal is:

A) sin^-1(1.00)
B) sin^-1(1/n₁)
C) sin^-1(1/n₂)
D) sin^-1(n₁/n₂)
E) sin^-1(n₂/n₁)