What is the unit of measurement for optical power of the lens?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. Diopter.
- The unit of measurement for the optical power of a lens is the diopter (D).
- The optical power of a lens is defined as the reciprocal of its focal length (in meters). If a lens has a focal length of 1 meter, its optical power is 1 diopter. If the focal length is shorter, the power increases, and if the focal length is longer, the power decreases.