Assertion : The resolving power of a telescope is more if the diameter of the objective lens is more.
Reason : Objective lens of large diameter collectd more light.

Options

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

Explanation

To solve the assertion and reason question, we will analyze both the assertion and the reason step by step.

### Step 1: Analyze the Assertion
The assertion states: "The resolving power of a telescope is more if the diameter of the objective lens is more."

- **Resolving Power Definition**: The resolving power of a telescope is its ability to distinguish between two closely spaced objects. It is given by the formula:
\[ \text{Resolving Power} = \frac{D}{1.22 \lambda} \]
where \(D\) is the diameter of the objective lens and \(\lambda\) is the wavelength of light used.

- **Conclusion from Assertion**: From the formula, we can see that the resolving power is directly proportional to the diameter \(D\). Therefore, if the diameter of the objective lens increases, the resolving power also increases. Thus, the assertion is **True**.

### Step 2: Analyze the Reason
The reason states: "Objective lens of large diameter collects more light."

- **Light-Gathering Power**: The light-gathering power of a lens is also related to its diameter. A larger diameter allows the lens to collect more light, which improves the brightness of the image formed.

- **Conclusion from Reason**: This statement is also **True**. However, while it is true that a larger diameter collects more light, this does not directly explain why the resolving power is greater. The resolving power is a function of the diameter but is not solely dependent on the amount of light collected.

### Final Conclusion
- Both the assertion and the reason are true.
- However, the reason does not correctly explain the assertion.

Thus, the correct answer is **Option B**: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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