weber
Magnetic fluxexact by definition
The weber is the SI unit of magnetic flux, the total magnetic field passing through a surface. One weber is the flux which, falling to zero in one second, induces one volt in a single-turn loop around it, so the weber equals one volt second exactly. As a coherent derived SI unit its relation to the base units is exact by definition.
Watch out: The CGS unit of flux is the maxwell, equal to exactly 1e-8 weber, and it still appears in older magnetics literature alongside the gauss. Flux in webers is not the same quantity as flux density in teslas: one weber spread over one square metre is one tesla, and the same flux through a smaller area is a stronger field.
| 1 Wb | 1 Wb |
Named for Wilhelm Eduard Weber, Gauss's collaborator on absolute magnetic measurement and the builder of an early electromagnetic telegraph at Göttingen.