The beam hits the glass surface at an angle of 60. What is the angle of refraction?

In accordance with the law of refraction, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant value. This value is called the refractive index:

n = sinα / sinβ,

whence the angle of refraction is

β = arcsin (sinα / n);

β = arcsin (sin60 ° / 1.73) = arcsin (0.5) = 30 °.