Statement-I : X-rays can be emitted by the excited atoms.
Statement-II : `gamma` -rays can be emitted by the excited nuclei.

Options

A. If both Statement- I and Statement- II are true, and Statement - II is the correct explanation of Statement– I.
B. If both Statement - I and Statement-II are true but Statement - II is not the correct explanation of Statement – I.
C. If Statement-I is true but Statement-II is false.
D. If Statement-I is false but Statement-II is true.

Answer

To solve the question, we need to analyze both statements regarding X-rays and gamma rays and determine their validity and relationship.

### Step-by-Step Solution:

1. **Understanding Statement-I**:
- The statement claims that "X-rays can be emitted by excited atoms."
- This is true. When an atom is excited (for example, when an electron is knocked out of an inner shell), an electron from a higher energy level can fall into the lower energy level to fill the vacancy. This transition releases energy in the form of X-rays.

2. **Understanding Statement-II**:
- The statement claims that "gamma rays can be emitted by excited nuclei."
- This is also true. When a nucleus is in an excited state (often after undergoing radioactive decay), it can release energy as it transitions to a lower energy state, emitting gamma rays in the process.

3. **Analyzing the Relationship**:
- While both statements are true, the second statement does not serve as a reason for the first statement. The processes of X-ray emission and gamma-ray emission occur in different contexts (atomic vs nuclear) and are not directly related.

4. **Conclusion**:
- Both statements are correct, but Statement-II is not the correct reason for Statement-I. Therefore, the correct option is that both statements are true, but the second statement is not the correct reason for the first statement.

### Final Answer:
- The correct option is: **Option 2** - Both Statement-I and Statement-II are correct, but Statement-II is not the correct reason for Statement-I.

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