Assertion : Critical angle of light while passing from glass to air is minimum for violet colour.
Reason : The wavelength of violet li^ht is greater than that of other colours

Options

A. If both assertion and reason are true and\ reason is a correct explanation of the assertion
B. If both assertion and reason are true but the reason is not a correct explanation of assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the critical angle of light while passing from glass to air is minimum for violet color.
- The critical angle (ic) can be determined using Snell's law, which states that \( n_1 \sin(i) = n_2 \sin(r) \). At the critical angle, the angle of refraction (r) is 90 degrees, meaning that light is refracted along the boundary.

2. **Applying Snell's Law**:
- For light passing from glass (with refractive index \( n_g \)) to air (with refractive index \( n_a \)), we can express the critical angle as:
\[ n_g \sin(i_c) = n_a \sin(90^\circ) \]
- Since \( \sin(90^\circ) = 1 \), this simplifies to:
\[ n_g \sin(i_c) = n_a \]
- Rearranging gives:
\[ \sin(i_c) = \frac{n_a}{n_g} \]
- Therefore, the critical angle is:
\[ i_c = \sin^{-1}\left(\frac{n_a}{n_g}\right) \]

3. **Refractive Index and Wavelength**:
- The refractive index \( n \) is inversely related to the wavelength of light in a medium. Violet light has the shortest wavelength among visible light, which means it has the highest refractive index in glass.
- As the refractive index increases, the critical angle decreases. Thus, since violet light has the highest refractive index, it will have the minimum critical angle.

4. **Evaluating the Reason**:
- The reason states that the wavelength of violet light is greater than that of other colors. This is incorrect. In fact, violet light has the shortest wavelength compared to other colors in the visible spectrum.
- Therefore, the reason provided does not support the assertion.

5. **Conclusion**:
- The assertion is true: the critical angle of light while passing from glass to air is minimum for violet color.
- The reason is false: the wavelength of violet light is not greater than that of other colors; it is, in fact, the shortest.

### Final Answer:
- Assertion: True
- Reason: False