A lens of focal length 40 mm is used as a magnifier.The object being viewed is 5.3 mm long,and is positioned at the focal point of the lens.The user of the magnifier has a near point at 25 cm.The angular magnification of the magnifier is closest to:
A)6.3
B)5.6
C)6.9
D)7.5
E)8.1

Question

Quizplus · Accepted Answer

The angular magnification (M) of a magnifier is given by M = 1 + (D/f), where D is the near point distance (25 cm) and f is the focal length of the lens (40 mm or 4 cm). Substituting the values, M = 1 + (25/4) = 7.25, which is closest to 6.3.

A Lens of Focal Length 40 Mm Is Used as a Magnifier.The