In Figure, light enters a 90? triangular prism at point P with incident angle , and then some of it refracts at point Q with

In Figure, light enters a 90? triangular prism at point P with incident angle θ, and then some of it refracts at point Q with an angle of refraction of 90?.

(a) What is the index of refraction of the prism in terms of θ?

(b) What, numerically, is the maximum value that the index of refraction can have? Does light emerge at Q if the incident angle at P is

(c) Increased slightly and

(d) Decreased slightly?

Air P.