Question

Which of the following will show Tyndall effect? How can you observe the Tyndall effect in them?
(a) Salt Solution
(b) Milk
(c) Solution of Copper Sulphate
(d) Starch Solution

Answer 1

(b) and (d) Milk and starch solution exhibit Tyndall effect.
The Tyndall effect is the mechanism in which the particles in a colloid scatter the rays of light that are directed at them. All colloidal solutions and some very fine suspensions exhibit this effect. Therefore, it can be used to confirm if a given solution is a colloid. Scattered light intensity depends on the colloidal particle density as well as the incident light frequency.

• Milk makes of a colloid comprising fat and protein globules. The light is spread when a beam of light is directed at a glass of milk. This is a perfect description of the Tyndall effect.
• The direction of the light becomes evident when a torch is turned on in a foggy atmosphere. The water droplets in the fog are accountable for the scattering of light in this case.