Consider an optical fiber having a core index of 1.46 and a cladding index of 1.45.
a) What is the critical angle for this core-cladding interface?
b) For what range of angles inside the fiber at the entrance to the fiber (θ2) will light be totally internally reflected at the upper edge of the fiber?
c) To what range of incidence angles (θ1) does this correspond?
d) How will that range of incidence angles in part (c) be changed if the fiber is submersed in water rather than air?