What is the power of a lens that has a focal length of -40 cm and a width of 2.0 cm?
A) +4.0 diopters
B) -2.5 diopters
C) -0.50 diopters
D) -50 diopters
E) +2.5 diopters

Question

Quizplus · Accepted Answer

The power of a lens (P) is given by the formula P = 1/f, where f is the focal length in meters. Converting -40 cm to meters gives -0.40 m. Therefore, P = 1/(-0.40) = -2.5 diopters. The width of the lens is not relevant for calculating its power.

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