Adiamond is underwater; a light ray enters one face of the diamond, then travels at an angle of 30 degrees with respect to the normal. what was the ray's angle of incidence on the diamond? the index of refraction of water is nwater=1.33, and the index of refraction of diamond is ndiamond=2.42. finally, apply snell's law and find the ray's angle of incidence θ1 on the diamond.