The unit is derived (through Faraday's law of induction) from the relationship 1 Wb = 1 V⋅s (volt-second).
A magnetic flux density of 1 Wb/m2 (one weber per square metre) is one tesla.
Officially:Weber (unit of magnetic flux) — The weber is the magnetic flux that, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second.
The weber is commonly expressed in a multitude of other units[citation needed]:
As with every SI unit named for a person, its symbol starts with an upper case letter (Wb), but when written in full, it follows the rules for capitalisation of a common noun; i.e., weber becomes capitalised at the beginning of a sentence and in titles but is otherwise in lower case.
In 1861, the British Association for the Advancement of Science (known as "The BA"[4]) established a committee under William Thomson (later Lord Kelvin) to study electrical units.
[5] In a February 1902 manuscript, with handwritten notes of Oliver Heaviside, Giovanni Giorgi proposed a set of rational units of electromagnetism including the weber, noting that "the product of the volt into the second has been called the weber by the B.
"[6] The International Electrotechnical Commission began work on terminology in 1909 and established Technical Committee 1 in 1911, its oldest established committee,[7] "to sanction the terms and definitions used in the different electrotechnical fields and to determine the equivalence of the terms used in the different languages.
"[8] It was not until 1927 that TC1 dealt with the study of various outstanding problems concerning electrical and magnetic quantities and units.
Discussions of a theoretical nature were opened at which eminent electrical engineers and physicists considered whether magnetic field strength and magnetic flux density were in fact quantities of the same nature.
As disagreement continued, the IEC decided on an effort to remedy the situation.
"[12] In 1938, TC24 "recommended as a connecting link [from mechanical to electrical units] the permeability of free space with the value of μ0 = 4π×10−7 H/m".
[9] "After consultation, the ampere was adopted as the fourth unit of the Giorgi system in Paris in 1950.
"[11] Like other SI units, the weber can modified by adding a prefix that multiplies it by a power of 10.