Percutaneous endoscopic gastrostomy (PEG): A surgical procedure for placing a feeding tube without having to perform an open laparotomy (operation on the abdomen). The aim of PEG is to feed those who cannot swallow. PEG may be done by a surgeon, gastroenterologist (GI specialist).
While the intensity of a sound is a very objective quantity that can be measured with sensitive instrumentation, the loudness of a sound is more of a subjective response that will vary with a number of factors.
Sound intensity is defined as the sound power per unit area. The usual context is the measurement of sound intensity in the air at a listener's location. The basic units are watts/m2 or watts/cm2 . Many sound intensity measurements are made relative to a standard threshold of hearing intensity I0 :