dB⃗=μ04π I dl⃗×r^r2d\vec{B} = \frac{\mu_0}{4\pi}\,\frac{I\,d\vec{l}\times\hat{r}}{r^2} dB=4πμ0r2Idl×r^
∮B⃗⋅dl⃗=μ0I\oint \vec{B}\cdot d\vec{l} = \mu_0 I ∮B⋅dl=μ0I
∇⋅B⃗=0\nabla\cdot\vec{B} = 0 ∇⋅B=0
F⃗=q v⃗×B⃗\vec{F} = q\,\vec{v}\times\vec{B} F=qv×B