Neumann's mutual-inductance formula
= Neumann's mutual-inductance formula
{c}
For thin closed wire loops $C_1,C_2$, the mutual inductance is
$$
L_{12}=L_{21}
=\frac{\mu_0}{4\pi}
\oint_{C_1}\oint_{C_2}
\frac{dx_1\cdot dx_2}{|x_1-x_2|}.
$$
= Neumann's mutual-inductance formula
{c}
For thin closed wire loops $C_1,C_2$, the mutual inductance is
$$
L_{12}=L_{21}
=\frac{\mu_0}{4\pi}
\oint_{C_1}\oint_{C_2}
\frac{dx_1\cdot dx_2}{|x_1-x_2|}.
$$