Answer: (2) and (4) Milk and starch solution exhibits 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.
Examples of the Tyndall effect
- 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.