If you are watching a football game from the end of a large stadium, (a) what size will be the image of the football (L=0.3m) on your retina when the football is at the end of the field, 150m away from your seat? Assume that the diameter of the eyeball (image distance) is 2.5cm. (b) What is the focal length of the lens system of the eye when focused at this distance? (c) What is the focal length of the eye when the football is only 3m away?

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