The figure (a) shows the basicstructure of a human eye. Light refracts into the eye through thecornea and is then further redirected by a lens whose shape (andthus its ability to focus the light) is controlled by muscles. Wecan treat the cornea and eye lens as a single effective thin lens(figure (b)). A "normal" eye can focus parallel light rays from adistant object O to a point on the retina at the back of the eye,where processing of the visual information begins. As an object isbrought close to the eye, however, the muscles must change theshape of the lens so that rays from an inverted real image on theretina (figure (c)). Suppose that for the parallel rays of figures(a) and (b), the focal length of the effective thin lens of the eyeis 2.7 cm. For an object at a distance p = 26.0 cm, what focallength f' of the effective lens is required for it to be seenclearly?
