Ans. The eye has different adjusting mechanics for focusing the image of an object onto the retina. Its ciliary muscles control the curvature and thus the focal length of the lens, and allow objects at various distances to be seen.
s If an object is far away from the eye, the deviation of light through the lens must be less To do this, the ciliary muscles relax and decrease the curvature of the lens, thereby increasing the focal length. The rays are thus focused onto the retina producing a sharp image of the distant object.
objects at various to be seen
Flg.1 2.33 Human ay» accommodation If an object is close to the eye, the ciliary muscles increase curvature of the lens, thereby, shorter, nig the focal length. The divergent rays from the nearer object are thus bent more so as to come to a focus on the retina.