(dB) n. one tenth of a bel: a unit for comparing levels of power (especially sound) on a logarithmic scale. A power source of intensity P has a power level of 10 log10P/P0 decibels, where P0 is the intensity of a reference source. The decibel is much more widely used than the bel. Silence is 0 dB; a whisper has an intensity of 30 dB, normal speech 60 dB, a shout 90 dB, and a jet aircraft 120 dB.
Subjects: Science and Mathematics — Medicine and Health.