Final answer:
The aperture diameter of the 16mm focal length lens set to f/4.0 is 4mm.
Step-by-step explanation:
The aperture diameter of a lens is determined by the f-number.
The f-number is defined as the ratio of the focal length of the lens to the diameter of the aperture.
In this case, the focal length of the lens is given as 16 mm and the aperture is set to f/4.0.
To find the aperture diameter, we can use the formula:
Aperture diameter = focal length / f-number
Substituting the given values:
Aperture diameter = 16 mm / 4.0
= 4 mm
Therefore, the aperture diameter of the 16 mm focal length lens set to f/4.0 is 4 mm.