The phenomenon of scattering of light by colloidal particle is called……………

Answer

**Step-by-Step Solution:**

1. **Understanding Colloidal Particles**:
Colloidal particles are small particles that range in size from 1 nanometer to 1000 nanometers. They are larger than molecules but smaller than particles that can be seen with the naked eye.

2. **Wavelength of Light**:
The wavelength of visible light ranges from approximately 390 nanometers to 700 nanometers. This range overlaps with the size of colloidal particles.

3. **Scattering of Light**:
When light passes through a colloidal solution, it interacts with the colloidal particles. Due to their size, these particles can scatter the light in various directions.

4. **Visibility of Light Path**:
As the light scatters off the colloidal particles, it makes the path of the light visible. This is because the scattered light can be seen by an observer.

5. **Naming the Phenomenon**:
The phenomenon of light scattering by colloidal particles is specifically called the "Tyndall effect."

6. **Example of Tyndall Effect**:
A common example of the Tyndall effect is when light passes through a colloidal solution like milk. The path of the light becomes visible due to the scattering by the fat globules present in the milk.

**Final Answer**: The phenomenon of scattering of light by colloidal particles is called the **Tyndall effect**.

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