A cell phone is placed 40 cm in front of a converging lens with a focal length of magnitude 20 cm. How far is the image of this phone from the lens?
A) 10 cm
B) 40 cm
C) 60 cm
D) 20 cm
E) 13 cm

Question

Quizplus · Accepted Answer

Using the lens equation 1/f = 1/v + 1/u, where f is the focal length, v is the image distance, and u is the object distance. Given f = 20 cm and u = -40 cm (object distance is considered negative in lens formula), solving for v gives v = 40 cm.

A Cell Phone Is Placed 40 Cm in Front of a Converging