A reader's near point has receded to 75 cm from his eye; he cannot focus anything closer
PHYSICS · Subjective · Fermi University Physics · Optics & Photonics · Geometrical optics and imaging · Geometrical optics and imaging
Optics and Photonics, Ch Stops, pupils and optical instruments
Problem
A reader's near point has receded to 75 cm from his eye; he cannot focus anything closer. He wishes to read a page held at the standard near point d0=250 mm. A thin spectacle lens, treated as being in contact with the eye and surrounded by air, must image the page at his own near point so that his eye can focus it. Use the book's convention (so>0 for a real object to the left, si>0 for a real image to the right). What dioptric power D is required, to two significant figures?