Concept:
Thermal expansion is the tendency of matter to change its shape, area, and volume in response to a change in temperature. For solid materials, the change in length ($\Delta L$) is directly proportional to the original length ($L_0$) and the change in temperature ($\Delta T$).
Step 1: Identify the given values.
• Original length ($L_0$) = 1 m
• Change in length ($\Delta L$) = 1 mm = $10^{-3}$ m
• Change in temperature ($\Delta T$) = 100°C
Step 2: Apply the formula for linear expansion.
The coefficient of linear expansion ($\alpha$) is given by:
\[ \Delta L = L_0 \alpha \Delta T \]
Rearranging for $\alpha$:
\[ \alpha = \frac{\Delta L}{L_0 \Delta T} \]
Step 3: Calculate the final value.
Substituting the values:
\[ \alpha = \frac{10^{-3}}{1 \times 100} \]
\[ \alpha = \frac{10^{-3}}{10^2} \]
\[ \alpha = 10^{-5} / \text{°C} \]