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