Suppose a ray of light traveling in a material with an index of refraction na reaches an interface with a material having an index of refraction nb.

which of the following statements must be true for total internal reflection to occur?
1.the angle of incidence must be less than the critical angle. na = nb2/the angle of incidence must be equal to the critical angle. na > nb3.the angle of incidence must be greater than the critical angle.