Refractive index of a transparent material is :

Options

A. same for all colours.
B. maximum for violet colour.
C. minimum for violet colour.
D. maximum for red colour.

Explanation

To solve the question regarding the refractive index of a transparent material, we need to understand how the refractive index varies with color (or wavelength) of light.

### Step-by-Step Solution:

1. **Understanding Refractive Index**:
The refractive index (n) of a material is defined as the ratio of the speed of light in vacuum (c) to the speed of light in the material (v). Mathematically, it is given by:
\[ n = \frac{c}{v} \]

2. **Dependence on Wavelength**:
The refractive index of a material is not constant for all wavelengths of light. It generally varies with the wavelength due to the phenomenon known as dispersion.

3. **Color and Wavelength**:
Different colors of light correspond to different wavelengths. Violet light has the shortest wavelength among visible light, while red light has the longest wavelength.

4. **Frequency and Refractive Index**:
The refractive index is inversely related to the wavelength of light. This means that as the wavelength decreases (which corresponds to an increase in frequency), the refractive index increases. Since violet light has the highest frequency (and thus the shortest wavelength), it will have the highest refractive index.

5. **Conclusion**:
Therefore, the refractive index of a transparent material is maximum for violet color.

### Final Answer:
The correct option is **maximum for violet color** (Option 2).

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