Wave per unit distance (typically per meter), can be associated with the wavelength by the relation The period formula_33 is the time for one complete cycle of an oscillation of a wave. The frequency formula_34 is the number of periods per unit time (per second) and is typically measured in hertz denoted as Hz. These are related by: In other words, the frequency and period of a wave are reciprocals. The angular frequency formula_28 represents the frequency in radians per second. It is related to the frequency or period by The wavelength formula_30 of a sinusoidal waveform traveling at constant speed
Sound power temperature, the sound power level at distance "r" from the sound source is approximately related to sound pressure level (SPL) by where Derivation of this equation: For a "progressive" spherical wave, where "z" is the characteristic specific acoustic impedance. Consequently, and since by definition , where is the reference sound pressure, The sound power estimated practically does not depend on distance. The sound pressure used in the calculation may be affected by distance due to viscous effects in the propagation of sound unless this is accounted for. Sound power Sound power or acoustic power is the rate at which sound