Question

Explain Tyndall effect.

Answer 1

Tyndall effect

1. The Tyndall effect is the phenomenon in which the particles in a colloid scatter the beams of light that are directed at them.
2. This effect is exhibited by all colloidal solutions and some very fine suspensions.
3. Therefore, it can be used to verify if a given solution is a colloid.
4. The intensity of scattered light depends on the density of the colloidal particles as well as the frequency of the incident light.
5. When a beam of light passes through a colloid, the colloidal particles present in the solution do not allow the beam to completely pass through.
6. The light collides with the colloidal particles and is scattered (it deviates from its normal trajectory, which is a straight line).
7. The diameters of the particles that cause the Tyndall effect can range from$40-900\mathrm{nanometers}\left(1\mathrm{nanometer}={10}^{-9}\right)$.
8. The Tyndall effect was first discovered by the Irish physicist John Tyndall.

Example :

• Milk is a colloid that contains globules of fat and protein. When a beam of light is directed at a glass of milk, the light is scattered. This is a great example of the Tyndall effect.