Final answer:
The focal length required for a clear image to form on the retina when a book is 34.9 cm away from the eye is approximately 1.93 cm.
Step-by-step explanation:
The student's question pertains to the focal length of the eye's lens/cornea system when a clear image is formed on the retina.
To solve this, we use the thin lens formula 1/f = 1/do + 1/di, where f is the focal length of the lens, do is the distance of the object from the lens, and di is the distance of the image from the lens.
In this case, do = 34.9 cm (distance from the eye to the book) and di corresponds to the lens-to-retina distance, which is typically about 2.00 cm.
Applying the formula, we get 1/f = 1/34.9 + 1/2.00, leading to f ≈ 1.93 cm.
Thus, the focal length required for a clear image to form on the retina when the book is 34.9 cm away is approximately 1.93 cm.