Sound Waves

Sound waves are longitudinal waves that propagate through a medium by creating alternating regions of compression and rarefaction. These mechanical waves transfer energy through various media, including air, water, and solids.

Wave Properties

Wave Speed in Air

v=331.3+0.606Tv = 331.3 + 0.606T

where T is temperature in °C

Frequency and Pitch

  • Human hearing range: 20 Hz - 20 kHz
  • Higher frequency = Higher pitch
  • Lower frequency = Lower pitch

Sound Intensity

Sound intensity level in decibels:

β=10log⁡10(II0)\beta = 10 \log_{10}\left(\frac{I}{I_0}\right)

where:

  • β is the sound level in dB
  • I is the intensity
  • I₀ is the reference intensity (10⁻¹² W/m²)

Applications

  • Musical instruments
  • Medical ultrasound
  • Sonar systems
  • Noise control