Assertion :- (a) the total number of atoms present in a simple cubic unit cell is one .
Reasn :-(R ) simple cubic cell has atoms at its corners , each of which is shered between eight adjecent adjeacent unit cells.

Options

A. Assertion and reason both are corrent statements and reason is correct explanation for assertion.
B. Assertion and reason both are corrent statements but reason is not correct explanation for assertion.
C. Assertion is corrent statement but reason reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.

Explanation

To solve the question regarding the assertion and reason related to the simple cubic unit cell, we will break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the total number of atoms present in a simple cubic unit cell is one.

2. **Understanding the Reason**:
- The reason provided states that a simple cubic cell has atoms at its corners, each of which is shared between eight adjacent unit cells.

3. **Analyzing the Simple Cubic Unit Cell**:
- A simple cubic unit cell has atoms located at each of its eight corners.

4. **Calculating the Contribution of Corner Atoms**:
- Each corner atom is shared by eight adjacent unit cells. Therefore, the contribution of each corner atom to the unit cell is \( \frac{1}{8} \).

5. **Total Contribution from All Corners**:
- Since there are 8 corners in a simple cubic unit cell, the total contribution of atoms from the corners can be calculated as follows:
\[ \text{Total atoms} = 8 \times \frac{1}{8} = 1 \]

6. **Conclusion on Assertion**:
- The assertion is correct because the total number of atoms in a simple cubic unit cell is indeed one.

7. **Conclusion on Reason**:
- The reason is also correct as it accurately describes how the corner atoms are shared among adjacent unit cells.

8. **Final Evaluation**:
- Since both the assertion and the reason are correct, and the reason correctly explains the assertion, we conclude that both statements are true.

### Final Answer:
- The correct answer is that both the assertion and reason are correct, and the reason is the correct explanation for the assertion.