- rayl
- one of two units of sound impedance. When sound waves pass through any physical substance the pressure of the waves causes the particles of the substance to move. The sound impedance is the ratio between the pressure and the particle velocity it produces. The impedance is 1 rayl if unit pressure produces unit velocity. In MKS units, this means 1 rayl equals 1 pascal-second per meter (Pa·s/m), or (equivalently) 1 newton-second per cubic meter (N·s/m3). Confusingly, the same name, rayl, is used for the corresponding CGS unit, 1 dyne-second per cubic centimeter (dyn·s/cm3). The CGS rayl equals 10 MKS rayls. The units are named for Robert John Strutt, the fourth Lord Rayleigh (1875-1947).
Dictionary of units of measurement. 2015.