Question

The coefficient of linear expansion of a solid depends on

• A. its initial length
• B. the variation in temperature
• C. the nature of the material
• D. the external pressure
• E. the mass of the solid

Hint:

Think of coefficients like "DNA" for materials. Just like density or specific heat, the coefficient of expansion describes \textit{what} the material is, not how much of it you have.

Answer 1

The Correct Option is C

Concept:
Physics - Thermal Properties of Matter.
Step 1: Examine the formula for linear expansion.
The change in length ($\Delta L$) is given by: $$ \Delta L = L_0 \alpha \Delta T $$ Where $\alpha$ is the coefficient of linear expansion.
Step 2: Analyze the variable $\alpha$.
While the total \textit{expansion} ($\Delta L$) depends on length and temperature, the \textit{coefficient} ($\alpha$) is a characteristic property of the substance itself.
Step 3: Evaluate the dependencies.
Different materials (like steel, copper, or aluminum) expand by different amounts for the same temperature rise because their atomic structures and bond strengths differ.
Step 4: Conclusion.
Therefore, $\alpha$ is independent of dimensions like mass or length and depends solely on the nature of the material.