A far sighted person can not see clearly objects that are closer to his eyes than 60.0 cm. Which one of the following combinations represents the correct focal length and the refractive power of the contact lenses that will enable him to see the objects at a distance of 25.0 cm from his eyes?
A) -42.9 cm, +2.33 diopters
B) -42.9 cm, -2.33 diopters
C) +42.9 cm, +2.33 diopters
D) +42.9 cm, -2.33 diopters
E) +60 cm, +42.9 diopters

Question

Quizplus · Accepted Answer

A far-sighted person needs converging lenses, which have a positive focal length. The lens formula (1/f = 1/v - 1/u) is used to calculate the focal length needed to see objects at 25 cm, given the near point is 60 cm. The refractive power is the inverse of the focal length in meters, resulting in +2.33 diopters.

A Far Sighted Person Can Not See Clearly Objects That