Chapter 25, Problem 13P

A 40-year-old optometry patient focuses on a 6.50-cm-tall photograph at his near point. (See Table 25.10) We can model his eye as a sphere 2.50 cm in diameter, with a thin lens at the front and the retina at the rear (a) What is the effective focal length of his eye and its power in diopters when he focuses on the photo? (b) How tall is the image of the photo on his retina? Is it upright or inverted? Real or virtual? (c) If he views the photograph from a distance of 2.25 m, how tall is its image on his retina?

Table 25.1 Receding of near point with age

Age (years)	Near point (cm)
10	7
20	10
30	14
40	22
50	40
60	200