Of the following, the most elastic material is

Options

A. iron
B. rubber
C. diamond
D. copper

Answer

To determine the most elastic material among the given options, we need to understand the concept of elasticity and Young's modulus. Here's a step-by-step solution:

### Step 1: Understand Elasticity
Elasticity is the ability of a material to return to its original shape after being deformed. The measure of elasticity is quantified by Young's modulus.

### Step 2: Define Young's Modulus
Young's modulus (E) is defined as the ratio of stress (force per unit area) to strain (deformation in length/original length). Mathematically, it is expressed as:
\[ E = \frac{F \cdot L}{A \cdot \Delta L} \]
Where:
- \( F \) = applied force
- \( L \) = original length
- \( A \) = cross-sectional area
- \( \Delta L \) = change in length

### Step 3: Analyze the Relationship
From the formula, we can see that for a material to have a high Young's modulus, it should have:
- A high ratio of stress to strain
- A smaller change in length (\( \Delta L \)) for a given stress

### Step 4: Compare Materials
Among the materials provided (assuming common examples like rubber, steel, and diamond), we need to identify which has the highest Young's modulus.

- **Rubber**: Low Young's modulus, highly elastic but deforms significantly.
- **Steel**: Moderate Young's modulus, good elasticity but not as high as diamond.
- **Diamond**: Very high Young's modulus, meaning it deforms the least under stress and is the most elastic.

### Step 5: Conclusion
Based on the analysis, diamond is the most elastic material among the options provided, as it has the highest Young's modulus and experiences the least change in length under stress.

### Final Answer
The most elastic material is **diamond**.

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