The focal length of a magnifying glass is 15 cm. If the near point of a person is 25 cm, what is the angular magnification of the glass for this person when his eyes are focused at infinity?
A) $1.7$
B) $2.7$
C) $3.7$
D) $5.7$
E) $4.7$

Question

The focal length of a magnifying glass is 15 cm. If the near point of a person is 25 cm, what is the angular magnification of the glass for this person when his eyes are focused at infinity? 
A) $1.7$
B) $2.7$
C) $3.7$
D) $5.7$
E) $4.7$

Quizplus · Accepted Answer

The angular magnification of a magnifying glass is given by the ratio of the near point distance of the eye to the focal length of the glass. In this case, the near point distance is 25 cm and the focal length is 15 cm, so the angular magnification is 25/15 = 1.7.

The Focal Length of a Magnifying Glass Is 15 Cm 1.71.71.7

The Focal Length of a Magnifying Glass Is 15 Cm $1.7$