Question

Help with part a, please!

Problem 4 In problem set 9, we briefly looked at how the intensity of light reaching the retina is strongly influenced by the pupil. In front of the pupil is the cornea and just behind is the lens, both of which work together to direct and focus light in the eye. Light first enters the eye through the cornea, is bent through the pupil, and then moves through the lens which is controlled by muscles that can control the focal length. As we age, the lens becomes less flexible, and people then need reading glasses in order to see close objects more clearly But even in young people, there's a limit to the flexibility of the lens and everyone has a "near point" (i.e., the closest point to their eye that they can see) and a "far point" (the furthest away that they can see A. Close one eye and hold your finger in front if you. In good light, you should be able to see the lines of your fingerprints. Bring your finger closer and closer until the fingerprint gets blurry. This is your near point. Enlist a friend, and use a piece of string to estimate the distance between your eye and your finger. The cornea is actually pretty thick, but we can approximate it as a thin lens centered about 4 mm into the surface of the eyeball. The cornea helps focus images onto your retina, which is about another 20 mm further back Using this information, figure out the minimum focal length of your cornea

Answer 1

near goi 四 Uz-25 -20 20 t25 芗