When a beam of light is passed through a colloidal solution, it gets scattered. This phenomenon is known as the Tyndall effect. The Tyndall effect is the scattering of light by particles in a colloidal solution or suspension. It is named after the Irish scientist John Tyndall, who first explained the phenomenon in the 19th century.

Explanation:

Scattering of Light:
Light is a form of electromagnetic radiation that travels in straight lines. When light encounters a medium, it can be transmitted, reflected, absorbed, or scattered. Scattering occurs when the light interacts with particles or objects in its path. These particles can be molecules, atoms, or larger particles like colloidal particles.

Colloidal Solution:
A colloidal solution is a heterogeneous mixture in which particles are dispersed in a medium. The particle size in a colloidal solution ranges from 1 to 1000 nanometers, which is larger than the size of individual molecules but smaller than the size of visible particles. Examples of colloidal solutions include fog, milk, and paint.

Tyndall Effect:
When a beam of light passes through a colloidal solution, the light interacts with the particles in the solution. The particles scatter the light in different directions, leading to the appearance of a visible beam. This scattering of light is known as the Tyndall effect.

The Tyndall effect is more pronounced in colloidal solutions compared to true solutions or suspensions. In a true solution, the particles are much smaller and do not scatter light significantly. In a suspension, the particles are larger and may settle down due to gravity, reducing the scattering effect.

Applications of the Tyndall Effect:
The Tyndall effect is used in various applications. Some of them are:

1. Fog lights: The scattering of light by fog particles improves visibility by making the light more visible to drivers.

2. Monitoring air pollution: The scattering of light by pollutants in the air can be used to monitor air quality and detect the presence of harmful particles.

3. Determining particle size: The intensity of scattering in a colloidal solution can be used to estimate the size of the particles present.

In conclusion, when a beam of light is passed through a colloidal solution, it gets scattered due to the interaction of light with the particles in the solution. This scattering of light is known as the Tyndall effect.