Question

Select the most appropriate word from the given box and fill in the following blanks.

refracted diameter converging power convex small concave dioptre diverging focal length two aperture

One ______ is the power of a lens of focal length one metre.

Answer 1

One dioptre is the power of a lens of focal length one metre.

Explanation:

One dioptre is the SI unit of power of a lens, corresponding to a lens having a focal length of exactly 1 metre (1 D = 1 m⁻¹).