The focal length of a lens is 5 m. What is the refractive power of this lens in diopters?
A) 0.1 diopters
B) 0.2 diopters
C) 0.3 diopters
D) 0.4 diopters
E) 0.5 diopters

Question

Quizplus · Accepted Answer

The formula to calculate refractive power is: 
Refractive power (in diopters) = 1/focal length (in meters)
Therefore, in this case:
Refractive power = 1/5 = 0.2 diopters. 
Hence, option B is the answer.

The Focal Length of a Lens Is 5 M