Sound waves

Sound Waves

• Units and Variables

  • P - Pressure, in Pascals; Power, in Watts
  • s - Displacement amplitude
  • B - Bulk modulus
  • I - Intensity, power per unit area
  • I₀ - Referene intensity
  • β - Sound level, in decibels
• $v=\sqrt{\frac{B}{\rho }}=331\sqrt{1+\frac{T_c}{273}}$
• $\mathrm{\Delta P}={\mathrm{\Delta P}}_{\text{max}}\sin \left(\kappa x+\omega t\right)$
• $I=\frac{P}{A}=\frac{1}{2}\rho v{\left(\omega s_{\text{max}}\right)}^2$
• $I_0=1.00\times {10}^{-12}\frac{W}{m^2}$
• $\beta =10{\log }_{10}\left(\frac{I}{I_0}\right)$

• Doppler Effect

  • $f\prime =\left(\frac{v\pm v_O}{v\mp v_S}\right)f$
  • Use the top sign if moving toward source.