Which one of the following statements about the aperture of a convex l

Which one of the following statements about the aperture of a convex lens is correct ?

It is equal to its radius of curvature.
It is equal to its focal length.
It is independent of its radius of curvature.
It is equal to half of its focal length.
This question was previously asked in
UPSC CDS-2 – 2022
The aperture of a convex lens is the effective diameter of the circular outline of the lens from which light passes. It is related to the physical size of the lens and how much light it can collect. The aperture is independent of the lens’s radius of curvature and focal length. While these properties determine how the lens bends light, the aperture determines the brightness of the image and affects phenomena like diffraction and depth of field.
Aperture is a measure of the size of the opening that limits the amount of light passing through a lens. A larger aperture allows more light to enter, resulting in a brighter image and typically a shallower depth of field.
Focal length depends on the radii of curvature of the lens surfaces and the refractive index of the lens material (Lensmaker’s formula). Aperture is a geometric property related to the physical size of the lens or the diaphragm opening within it, and it can be adjusted in optical systems like cameras. It is not determined by or equal to the radius of curvature or focal length.