(1.20 points) In reality, the human eye is a complicated system with the cornea, lens, and vitreous humor all bending light. For simplicity, treat the eye like a hollow sphere with a single lens whose focal length can be varied.
a. (4 points) Estimate the focal length of this lens when viewing objects very far away.
b. (4 points) Estimate the focal length of the lens when viewing an object 25 cm away, about the closest you can focus.
c. (4 points) What is the percent difference between these two?
d. (4 points) When you try to look at things underwater, the image goes blurry. Thinking in terms of how refraction works, explain why this happens. (You may wish to consider the lensmaker's equation or the single surface image equation.)
e. (4 points) The Moken people overcome this by forcing their pupils to the minimum size.
i. Why does this help them see clearly underwater?
ii. What disadvantage does it bring?
