Question

Answer the following questions:
4. Power of a lens is 2 diopter. What does it mean?
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Answer 1

The lens power or diopter is defined as follows: That is, dividing 1000 by the focal length (in mm) of a lens yields the diopter of that lens. ... For example, if a lens has diopter +2, its focal length is 1000/2=500mm, and a lens of +4 diopter has focal length 1000/4 = 250mm