Assertion: Different colours of light have same velocity in vacuum, but they have different t velocities in in any other transparent medium.
Reason : v = c/`mu`, where symbols have standard meanings. For different colours, refractive index, oftransparent medium has different values. Therefore, v is different

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 the assertion and the reason given in the context of the principles of optics.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that different colors of light have the same velocity in a vacuum but different velocities in any other transparent medium.
- This is true because, in a vacuum, all electromagnetic waves (including light of different colors) travel at the same speed, denoted as \( c \) (approximately \( 3 \times 10^8 \) m/s).

2. **Understanding the Reason**:
- The reason provided states that the velocity of light in a medium is given by the formula \( v = \frac{c}{\mu} \), where \( \mu \) is the refractive index of the medium.
- It further explains that different colors of light have different refractive indices in a given medium, leading to different velocities for each color.

3. **Connecting Assertion and Reason**:
- The assertion is correct because it accurately describes the behavior of light in a vacuum and in other media.
- The reason is also correct as it explains the relationship between the speed of light in a medium and the refractive index, which varies for different colors of light.

4. **Conclusion**:
- Both the assertion and the reason are correct. The reason correctly explains why the assertion is true, making the relationship between them valid.

### Final Answer:
- Both the assertion and the reason are correct, and the reason correctly explains the assertion.

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