CBSE Class 12-science Answered

The colloidal solution shows the property of scattering of light. When light is passed though a colloidal solution, the rays are scattered. This phenomenon of scattering of light by colloidal particles present in the sols was first studied by Tyndall and is known as the Tyndall effect. The bright cone of scattered light is called Tyndall cone. When a beam of light is passed through a colloidal solution in a dark room, the solution becomes luminescent when seen through a microscope at right angle to the path of the incident light because of scattering of light by colloidal particles. The number of particles can be counted and it is also possible to decide the shapes of the particles roughly.