- Definition:reduction of amplitude or intensity when travelling
- Three forms:Absorption, scattering and reflection
- Unit: Decibel, dB
- Decibel (dB) =10 ×log(final intensity/initial intensity)
- Attenuation coefficient: dB change/distance
- Attenuation= attenuation coefficient (dB/cm)×path length
- Attenuation coefficient=frequency/2, meaning attenuation proportionally related to frequency