a) What is Tyndall effect? Give two examples for Tyndall effect.

Explanation

(a) The scattering of light by the particles in a colloidal medium is called Tyndall effect.
Examples :
Sunlight passing through a dense forest.
Focusing a beam of red light-in milk.
Passing a blue light to a dark room.
(b) The ability of eye to focus both near and distant objects, by adjusting the focal length is called power of accommodation of the eye. When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length increases and the distant objects are clearly visible to the eyes. To see the near by objects clearly, the ciliary muscles contract making the eye lens thicken. Thus the focal length of the eye lens decrease and the near by objects become visible to the eyes. Hence the human eye lens is able to adjust its focal length to view both distant objects