Twinkling of stars is due to atmospheric

Options

A. dispersion of light by water droplets
B. refraction of light by different layers of varying refractive indices
C. scattering of light by dust particles
D. internal reflection of light by clouds

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the reason behind the twinkling of stars. We need to identify the correct option that explains this phenomenon.

2. **Analyzing the Options**:
- **Option A**: "Expression of light by water droplet" - This option refers to how light interacts with water droplets, which is not the primary cause of twinkling.
- **Option B**: "Reflection of light by different layers of varying refractive index" - This option suggests that the light from stars is reflected by layers of the atmosphere, which could be a possible cause.
- **Option C**: "Scattering of light by dust particles" - While scattering can affect visibility, it does not specifically explain twinkling.
- **Option D**: "Interlinked reflection of light by clouds" - This option does not accurately describe the twinkling phenomenon.

3. **Identifying the Correct Concept**: The twinkling of stars is primarily caused by the refraction of light. As light from a star passes through different layers of the Earth's atmosphere, which have varying densities and temperatures, the light bends (or refracts) due to the change in refractive index.

4. **Conclusion**: Since the twinkling is caused by the bending of light (refraction) as it passes through these layers, the correct answer is **Option B**: "Reflection of light by different layers of varying refractive index."

5. **Final Answer**: The twinkling of stars is due to atmospheric refraction of light by different layers of varying refractive index.

---