A magnifying glass produces an angular magnification of 7. What is the focal length of this lens if a person whose near point is 28 cm reads a book using this magnifying glass?
A) 2 cm
B) 3 cm
C) 4 cm
D) 5 cm
E) 6 cm

Question

Quizplus · Accepted Answer

The angular magnification (M) of a magnifying glass is given by M = 1 + (D/f), where D is the near point distance (28 cm) and f is the focal length. Solving 7 = 1 + (28/f) gives f = 4 cm.

A Magnifying Glass Produces an Angular Magnification of 7