Question

The colour of light for which the refractive index of glass is minimum is:

• A. Red
• B. Yellow
• C. Green
• D. Violet

Answer 1

The Correct Option is A

Step 1: Understanding Refractive Index and Dispersion
The refractive index of a material varies with the wavelength (or colour) of light passing through it.
When white light traverses a prism or glass, it separates into its component colours. This phenomenon is termed dispersion.

Step 2: Relationship Between Refractive Index and Wavelength
- The refractive index exhibits an inverse relationship with the wavelength of light.
- Shorter wavelengths (e.g., violet) correspond to a higher refractive index.
- Longer wavelengths (e.g., red) correspond to a lower refractive index.

Step 3: Conclusion
Of all visible colours, red light possesses the longest wavelength, resulting in the lowest refractive index within glass.

Final Answer:
Red