A middle-aged man starts to wear eyeglasses with lenses of 2.0 D that allow him to read a book held as close as 25 cm. Several years later, he finds that he must hold a book no closer than 35 cm to read it clearly with the same glasses, so he gets new glasses.
What is the power of the new lenses?
P = 1/f (f in meters)
The Attempt at a Solution
P = 1/.35 = 2.9 (it was wrong)