As shown in Figure P35.73, a light ray is incident normal to one face of a 30°-60°-90° block of flint glass (a prism) that is immersed in water. (a) Determine the exit angle θ 3 of the ray. (b) A substance is dissolved in the water to increase the index of refraction n 2 . At what value of n 2 does total internal reflection cease at point P?
