bel

Unit expressing the relative intensity of a sound. The intensity in bels is the logarithm (to the base 10) of the ratio of the power of the sound to that of a reference sound. Ordinarily, the reference sound is assumed to be one with a power of 10⁻¹⁶ watts per sq cm, approximately the threshold of a normal human ear at 1000 Hz. [A.G. Bell, Scottish-U.S. scientist, 1847–1922]

* * *

blood ethanol level; bovine embryonic lung

* * *

bel 'bel n ten decibels abbr. b

Bell 'bel Alexander Graham (1847-1922)

American inventor. Bell began his career in the fields of speech and acoustics. Training teachers of the deaf, he and his father developed „visible speech,” a system of symbolic representations of the physical process of speech. His investigations into the application of electricity to the production and analysis of sound resulted in the invention of a multiplexing telegraph system. Further experimentation in telegraphy led to work on a method of electrically transmitting actual voice sounds, and in 1876 his work culminated in the invention of the telephone. Later inventions included a telephonic device using the modulation of a light beam, an audiometer, an improved phonograph, and an electrical induction device for the detection of metallic objects in the body. Throughout his life he remained deeply interested in the teaching of speech to the deaf.

* * *

n.

see decibel

* * *

(B) (bel) [Alexander Graham Bell, American inventor, 1847–1922] a unit of relative power intensity used for acoustic or electric power, defined as the base 10 logarithm of the ratio of the measured power to some reference power level. A change of one bel is a tenfold power increase. Measurements are usually expressed in decibels (q.v.).