Calculate the optical power of the human eye at the moment when its focal length is 20mm.

The optical power of a lens is denoted by the Latin letter D and is measured in diopters (diopters). It is calculated by the formula:

D = 1 / F

From the condition of the problem, we know that:

F = 20 mm

those. F = 20mm = 0.02m

Substituting the values into the formula, we get:

D = 1 / 0.02m = 50m-1

D = 50 diopters

Answer: The optical power of the human eye at the moment when its focal length is 20mm will be equal to 50 diopters.