6.10: Flux
( \newcommand{\kernel}{\mathrm{null}\,}\)
Recall from Section 1.8 that we defined two extensive scalar quantities for the electric field
ΦE=∬E⋅dA
and
ΦD=∬D⋅dA
which I called the E-flux and the D-flux, respectively. In an entirely similar manner I can define the B-flux and H-flux of a magnetic field by
ΦB=∬B⋅dA
and
ΦH=∬H⋅dA
The SI unit of ΦB is the tesla metre-squared, or T m2, also called the weber Wb. A summary of the SI units and dimensions of the four fields and fluxes might not come amiss here.
E | V m-1 | MLT-2Q-1 |
D | C m-2 | L-2Q |
B | T | MT-1Q-1 |
H | A m-1 | L-1T-1Q |
ΦE | V m | ML3T-2Q-1 |
ΦD | C | Q |
ΦB | Wb | ML2T-1Q-1 |
ΦH | A m | LT-1Q |