Why is there one with reference to a partial derivative of the magnetic field vector with respect to time while the other is a normal derivative of the magnetic flux?
Mathematically, they are the same. The only difference is that the d/dt in the second equation has been moved outside the integral, which is fine thanks to properties of integrals. You would use the first one if the integral of B is easier to solve and the second if dB/dt is easier to solve
Mathematically, they are the same. The only difference is that the d/dt in the second equation has been moved outside the integral, which is fine thanks to properties of integrals. You would use the first one if the integral of B is easier to solve and the second if dB/dt is easier to solve