Assertion : steel is more elastic than rubber.
Reason : For same strain , steel requires more stress to be produced in it.

Options

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

Answer

To solve the question regarding the assertion and reason about the elasticity of steel compared to rubber, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "steel is more elastic than rubber." This means that when both materials are subjected to stress, steel will return to its original shape more effectively than rubber when the stress is removed.

2. **Understanding the Reason**:
- The reason provided is "For the same strain, steel requires more stress to be produced in it." This implies that when both materials are stretched to the same extent (strain), the amount of force (stress) needed for steel is greater than that needed for rubber.

3. **Young's Modulus**:
- Young's modulus (Y) is a measure of the stiffness of a material and is defined as the ratio of stress (σ) to strain (ε):
\[ Y = \frac{\sigma}{\epsilon} \]
- Rearranging gives us:
\[ \sigma = Y \cdot \epsilon \]

4. **Comparing Steel and Rubber**:
- Let \( Y_s \) be the Young's modulus of steel and \( Y_r \) be the Young's modulus of rubber.
- For the same strain (ε), we can express the stress in both materials:
\[ \sigma_s = Y_s \cdot \epsilon \quad \text{(for steel)} \]
\[ \sigma_r = Y_r \cdot \epsilon \quad \text{(for rubber)} \]

5. **Ratio of Stress**:
- Dividing the stress equations for steel and rubber:
\[ \frac{\sigma_s}{\sigma_r} = \frac{Y_s}{Y_r} \]
- Since it is known that \( Y_s > Y_r \) (Young's modulus of steel is greater than that of rubber), it follows that:
\[ \frac{\sigma_s}{\sigma_r} > 1 \]
- This indicates that \( \sigma_s > \sigma_r \), meaning steel requires more stress than rubber for the same strain.

6. **Conclusion**:
- Since steel requires more stress to achieve the same strain, it is indeed more elastic than rubber. Therefore, both the assertion and the reason are correct.

### Final Answer:
- **Assertion**: True
- **Reason**: True
- **Explanation**: Steel is more elastic than rubber because it requires more stress to produce the same strain.