A : orbital angular momentum of(1s,2s,3s,etc) all s electrons is same
R : orbital angular momentum depends on orientation of orbitals .

Options

A. IF both assertion & reason are true and the reason is the correct explanation of the assertion then mark
B. IF both assertion & reason are true but the reason is not the correct explanation of the assertion , then mark
C. IF assertion is true statement but reason is false , then mark
D. If both assertion and reason are false statements then mark

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that the orbital angular momentum of all s electrons (1s, 2s, 3s, etc.) is the same.
- The orbital angular momentum (L) is determined by the azimuthal quantum number (l). For s orbitals, l = 0.
- Therefore, the orbital angular momentum for all s orbitals (1s, 2s, 3s, etc.) is indeed the same, which is L = 0.

2. **Understanding the Reason (R)**:
- The reason states that orbital angular momentum depends on the orientation of orbitals.
- Orbital angular momentum is influenced by the shape and orientation of the orbitals. The s orbitals are spherical and do not have a specific orientation in space.
- Since the s orbitals are spherical (l = 0), they do not exhibit any angular momentum due to orientation. Thus, the statement that orbital angular momentum depends on orientation is true, but it does not apply to s orbitals.

3. **Evaluating the Relationship**:
- Both the assertion and reason are true.
- However, the reason does not correctly explain the assertion because the assertion is about the fact that all s orbitals have the same angular momentum (which is zero), while the reason discusses the dependence of angular momentum on orientation, which is not applicable to s orbitals.

4. **Conclusion**:
- The assertion is true, and the reason is true, but the reason does not provide a correct explanation for the assertion. Therefore, the correct answer is that both A and R are true, but R is not the correct explanation for A.

### Final Answer:
- Both Assertion (A) and Reason (R) are true, but R is not the correct explanation for A.