Linear Thermal Expansion (ΔL/L = αl ΔT → L' = L(1 + αl ΔT))
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ΔL/L = αl ΔT → L' = L(1 + αl ΔT)
What each symbol means
| Symbol | What it stands for |
|---|---|
| L | Original length (m) |
| L' | New length after temperature change (m) |
| ΔL | Change in length (m) |
| ΔT | Change in temperature (K or °C) |
| αl | Coefficient of linear expansion (K⁻¹) |
When to use this
Valid for small temperature changes where αl is approximately constant. αl is characteristic of the material. Steel αl ≈ 1.2 × 10⁻⁵ K⁻¹, Copper αl ≈ 1.7 × 10⁻⁵ K⁻¹. If expansion is prevented, thermal stress σ = Yαl ΔT develops.