A beam of laser light with wavelength 612 nm is directed through a slab of glass having index of refraction 1.55.
(a) For what minimum incident angle would a ray of light undergo total internal reflection?
(b) If a layer of water is placed over the glass, what is the minimum angle of incidence on the glass-water interface that will result in total internal reflection at the water-air interface? (The beam of light is directed upward through the slab of glass, through the layer of water, and experiences total internal reflection at the water-air interface on top.)