DP 9.1 (50 points) [This problem is pertinent to Section 23-2 of the Textbook. ] A layer of oil (with n, = 1.45 ) floats on water (with n, =1.33.) A ray of light shines onto the oil with an incidence angle of 0, = 40.0 degrees with the normal, as shown in the figure. Suppose that the AW index of refraction for the air is n, = 1.00. Find the angle of refraction, say 0, , when the light ray enters the water. (Note that the angle of refraction } should be measured with respect to the normal.) DP 9.2 (50 points) [This problem is pertinent to Section 23-3 of the Textbook. ] A ray of light, emitted beneath the surface 13.4 cm of an unknown liquid with air above it, undergoes total internal reflection as shown in the figure. The critical angle of incidence is depicted and called 0, in this 15.0 cm figure. The index of refraction for the air is 12 = 1.00. What is the index of refraction n, for this unknown liquid