A seed is 15 mm in front of a converging lens, and the image of the seed is 4.0 mm behind the lens. What is the focal length of the lens? * Selected Answer: 3.2 mm Answers: 11 mm 3.2 mm 5.5 mm 3.8 mm A light ray in glass arrives at the glass-water interface an an angle of 9=48° with the normal. The refracted ray in water makes an angle the figure. The index of refraction of water is 1.33. The angle of incidence is now changed to 0 = 33°. What is the new angle of refraction water = 70° angle with the normal, as shown in in the water? glass ᎾᎥ Selected Answer: 44° Answers: 40° 48° 44° 46° 42°