A diamond (n = 2.42) immersed in glycerin (n = 1.473) liquid. What is the critical angle at the boundary between diamond and glycerin?

1 answer

It is not clear to me where the light is coming from, internal to the diamond trying to exit, or light in the glycerine trying to enter the diamond.
angle is arc sin (n2 / n1) where n1 is the incident ray, and 2 is the refracted ray
arcsin(1.473/2.42)=37.5 degrees (for light in the diamond trying to escape)