3.7.5.3
One weber is one tesla through one square metre
Magnetic Flux & Flux Linkage — AQA A-Level Physics
Key Definition
The weber (Wb) — One weber is the magnetic flux through a 1 m² area perpendicular to a uniform magnetic field of flux density 1 T. 1 Wb = 1 T m².
- The weberThe SI unit of magnetic flux. One weber is the flux through an area of 1 m² when the magnetic flux density is 1 T perpendicular to the area. is to flux what the teslaThe SI unit of magnetic flux density. One tesla is the flux density when a force of 1 N acts on a 1 m conductor carrying 1 A perpendicular to the field. is to flux densityMass per unit volume of a material. Measured in kg m⁻³.. The teslaThe SI unit of magnetic flux density. One tesla is the flux density when a force of 1 N acts on a 1 m conductor carrying 1 A perpendicular to the field. measures field strength per unit area. The weberThe SI unit of magnetic flux. One weber is the flux through an area of 1 m² when the magnetic flux density is 1 T perpendicular to the area. measures the total field through the whole area.
- 1 $Wb = 1 T m^{2}. You can always check this$ from the equation: $\Phi = BA gives units$ of T × $m^{2} = Wb$.
- In practice, webers tend to be quite large. Many real situations involve milliwebers (mWb) or even microwebers (μWb). A typical school magnet through a small coil might give a flux of a few mWb.
- The weberThe SI unit of magnetic flux. One weber is the flux through an area of 1 m² when the magnetic flux density is 1 T perpendicular to the area. is named after Wilhelm Weber, a 19th-century German physicist who worked on electromagnetism alongside Gauss.
Common Mistake
MEDIUM
Students often: Writing the unit of flux as 'T' (teslas) instead of 'Wb' (webers).
Instead: TeslaThe SI unit of magnetic flux density. One tesla is the flux density when a force of 1 N acts on a 1 m conductor carrying 1 A perpendicular to the field. is the unit of flux densityMass per unit volume of a material. Measured in kg m⁻³. (B). Weber is the unit of flux (Φ). They're related by 1 $Wb = 1 T m^{2}$, but they measure different things.
Instead: TeslaThe SI unit of magnetic flux density. One tesla is the flux density when a force of 1 N acts on a 1 m conductor carrying 1 A perpendicular to the field. is the unit of flux densityMass per unit volume of a material. Measured in kg m⁻³. (B). Weber is the unit of flux (Φ). They're related by 1 $Wb = 1 T m^{2}$, but they measure different things.