Blue colour of sky is due to phenomenon of :

Options

A. Reflection
B. Refraction
C. Scattering
D. Dispersion.

Answer

To determine why the sky appears blue, we can analyze the options provided and understand the underlying physics. Here’s a step-by-step solution:

### Step 1: Understanding the Atmosphere
The Earth is surrounded by an atmosphere composed of various gases and particles. This atmosphere interacts with sunlight that enters it.

**Hint:** Consider what happens when sunlight passes through the atmosphere.

### Step 2: Sunlight Composition
Sunlight, or white light, is made up of multiple colors, each with different wavelengths. The visible spectrum includes red, orange, yellow, green, blue, indigo, and violet, with blue light having a shorter wavelength compared to red light.

**Hint:** Recall the order of colors in the visible spectrum and their wavelengths.

### Step 3: Interaction of Light with Air Molecules
When sunlight enters the atmosphere, it interacts with the air molecules. The shorter wavelengths of light (like blue and violet) are scattered in all directions by these molecules more than the longer wavelengths (like red and yellow).

**Hint:** Think about how different wavelengths behave when they encounter small particles.

### Step 4: Scattering Phenomenon
The phenomenon responsible for the scattering of light is known as Rayleigh scattering. This scattering effect is more pronounced for shorter wavelengths, which is why blue light is scattered more than other colors.

**Hint:** Identify the specific type of scattering that affects shorter wavelengths.

### Step 5: Perception of Color
Although both blue and violet light are scattered, our eyes are more sensitive to blue light, and some of the violet light is absorbed by the ozone layer. As a result, we perceive the sky as predominantly blue.

**Hint:** Consider how human vision and atmospheric conditions influence color perception.

### Conclusion
Based on the analysis, the blue color of the sky is primarily due to the phenomenon of scattering, specifically Rayleigh scattering.

**Final Answer:** The blue color of the sky is due to the phenomenon of scattering.

### Summary of Steps:
1. Understand the atmosphere surrounding Earth.
2. Recognize the composition of sunlight.
3. Analyze how light interacts with air molecules.
4. Identify the scattering phenomenon (Rayleigh scattering).
5. Consider human perception of color in the atmosphere.