People with normal vision cannot focus their eyes underwater if they aren’t wearing a face mask or goggles and there is water in contact with their eyes. (a) Why not? (b) With the simplified model of the eye described in Exercise 34.52, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object?. Assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. Assume that the eyeglasses are 2.00 cm in front of the eye.)
People with normal vision cannot focus their eyes underwater if they aren’t wearing a face mask or goggles and there is water in contact with their eyes. (a) Why not? (b) With the simplified model of the eye described in Exercise 34.52, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object?. Assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. Assume that the eyeglasses are 2.00 cm in front of the eye.)
The front of the eye has two lenses, the cornea on the outside and another lens inside, to focus images on the retina, at the back of the eye. Most of the refraction takes place when light passes from the air into the cornea, which is much more dense, but water and the cornea have similar densities. So, when we open our eyes underwater, incoming light rays are hardly bent, or focused, at all. The inside lens bends the rays a little, but it can't make up for the lost corneal refraction, so the light that reaches the retina isn't focused and the underwater world looks blurry.
Step by step
Solved in 2 steps
