(a) Explain how a normal human eye is able to see distinctly the object placed at a distance as well as those placed at a nearer distance. (b) What is the far point and near point of a normal human eye?
(a) Ciliary muscles change the curvature of eye lens as per requirement of the eye. This changes the focal length of eye lens. When muscles are relaxed, lens becomes thin and distant objects are seen clearly. While seeing closer objects, muscles contract this thickens the eye lens and focal length decreases.
(b) Infinity, 25 cm from the eye.