Intensity of Sound Wave (I = 2π²ν²a²ρv)
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I = 2π²ν²a²ρv
What each symbol means
| Symbol | What it stands for |
|---|---|
| I | Intensity — energy transported per unit area per unit time (W/m²) |
| a | Amplitude of wave (m) |
| v | Speed of sound in medium (m/s) |
| ν | Frequency of sound wave (Hz) |
| ρ | Density of medium (kg/m³) |
When to use this
I ∝ a² (intensity proportional to square of amplitude). I ∝ ν² (proportional to square of frequency). For a point source, I ∝ 1/r² (inverse square law). Can also write I = ½ρω²a²v using ω = 2πν. Loudness (in dB) = 10 log₁₀(I/I₀) where I₀ = 10⁻¹² W/m².