edit The figure shows the velocity (dVdisplaystyle dV ) induced at a point P by an element of vortex filament (dLdisplaystyle dL ) of strength displaystyle Gamma. Retrieved 25 December 2011. If the conductor has some thickness, the proper formulation of the BiotSavart law (again in SI units) is: B(r)04V (JdV)rr3displaystyle mathbf B (mathbf r )frac mu _04pi iiint _V frac (mathbf J,dV)times mathbf r 'mathbf r '3 or, alternatively: B(r)04V (JdV)rr2displaystyle mathbf B (mathbf r )frac. Parker, 1994, isbn External links edit). Jackson, John David (1999). Hodgeson, 2nd Edition, 1978, John Murray, isbn The Cambridge Handbook of Physics Formulas,. In particular, it represents lines of inverse square law force.In electromagnetism the B lines form solenoidal rings around the source electric current, whereas in aerodynamics, the air currents form solenoidal rings around the source vortex axis. Magnetic responses applications edit The BiotSavart law can be used in the calculation of magnetic responses even at the atomic or molecular level,.g. These equations code promo pour mate9 were first derived by Oliver Heaviside in 1888. The law is valid in the magnetostatic approximation, and is consistent with both. Yet when we look at the B lines in isolation, we see exactly the aerodynamic scenario in so much as that B is the vortex axis and H is the circumferential velocity as in Maxwell's 1861 paper.