Assertion : 'Light year' and 'Wavelength' both measure distance.
Reason : Both have dimensions of time.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both , Assertion and Reason are true but Reason is not a correct explanation of the Assertion.
C. If Assertion is true but the Reason is false.
D. If both, Assertion and Reason are false.

Explanation

To analyze the given assertion and reason, we can break down the problem into a series of logical steps.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Light year" and "Wavelength" both measure distance.
- A light year is defined as the distance that light travels in a vacuum in one year. This is indeed a measure of distance.

2. **Understanding Wavelength**:
- Wavelength (often denoted by the Greek letter lambda, λ) is the distance between successive crests (or troughs) of a wave.
- Wavelength is also a measure of distance, typically measured in meters, nanometers, etc.

3. **Conclusion on the Assertion**:
- Both "Light year" and "Wavelength" are indeed measures of distance. Therefore, the assertion is **true**.

4. **Understanding the Reason**:
- The reason states that "Both have dimensions of time."
- However, this is incorrect.
- Light year is a measure of distance and has dimensions of length. Wavelength also has dimensions of length.

5. **Conclusion on the Reason**:
- Since the reason provided is incorrect, we conclude that the reason is **false**.

6. **Final Evaluation**:
- The assertion is true, but the reason is false. Thus, the final answer is that the assertion is true, but the reason is false.

### Final Answer:
C. Assertion is true but reason is false.

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