A person with normal eyesight uses a converging lens of focal length 10 cm. He holds the lens close to his eye to finish an engraving job. At what distance from the job he must hold the lens?
A) -7.1 cm
B) 7.1 cm
C) -30 cm
D) 30 cm
E) 20 cm

Question

Quizplus · Accepted Answer

For a person with normal eyesight using a converging lens, the lens formula 1/f = 1/v - 1/u can be used, where f is the focal length (10 cm), v is the image distance (at the near point of normal vision, 25 cm), and u is the object distance. Solving for u gives approximately 7.1 cm.

A Person with Normal Eyesight Uses a Converging Lens of Focal