Assertion : Steel is more elastic than rubber.
Reason : Under given deforming force, steel is deformed less than rubber.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is fa lse.
D. If the assertion and reason both are false.

Answer

To analyze the assertion and reason provided in the question, we need to understand the concepts of elasticity, stress, and strain.

### Step-by-Step Solution:

1. **Understanding Elasticity**:
- Elasticity is the property of a material to return to its original shape after the deforming force is removed.
- The measure of elasticity is often quantified by the Young's modulus (Y), which is defined as the ratio of stress (force per unit area) to strain (deformation per unit length).

2. **Assertion Analysis**:
- The assertion states: "Steel is more elastic than rubber."
- This means that steel can return to its original shape more effectively than rubber when the same deforming force is applied.

3. **Reason Analysis**:
- The reason states: "Under a given deforming force, steel is deformed less than rubber."
- This implies that when the same force is applied, the deformation (strain) experienced by steel is less compared to that of rubber.

4. **Connecting Assertion and Reason**:
- If steel is more elastic, it means that for the same amount of stress (force applied), it experiences less strain (deformation) compared to rubber.
- Therefore, both the assertion and the reason are true, and the reason explains why the assertion is true.

5. **Conclusion**:
- Both the assertion and reason are correct, and the reason provides a valid explanation for the assertion.

### Final Answer:
- The assertion is true: Steel is more elastic than rubber.
- The reason is also true: Under a given deforming force, steel is deformed less than rubber.
- The reason explains the assertion.