Felici's law

In physics, Felici's law allows one to calculate the net charge through a circuit configuration in which there is a current induced by a variable magnetic field, such a conductor coil immersed in a variable magnetic field. This law makes it possible to calculate net charge in a period using initial flux and final flux.

$q(t) = {1 \over \mathrm{R}} [\Phi(0) - \Phi(t)]$

Demonstration

$q(t) = \int_0^t i(\tau)d\tau = {1 \over \mathrm{R}}\int_0^t {f_{em}}(\tau)d\tau = {1 \over \mathrm{R}} [\Phi(0) - \Phi(t)]$

When ${f_{em}}(t)=- {d\Phi(t) \over dt}$