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Maxwell second equation

The Maxwell second law is also called "Gauss law of magnetism".

Statement:
It states that the total magnetic flux $$\psi_m$$ emerging through a closed surface is zero.

Integral form: 
$$\psi_m = \int B.ds = 0$$ .......(3)
Equ (3)  is the integral form of the Maxwell equation.
This equation also proves that the magnetic monopole does not exist.

Differential form:
Apply Gauss divergence theorem to equ (3).
That is:
$$\int_{s} B.ds = \int_{v} (\nabla.B) dV$$
Since:
$$\int B.ds =0$$
Thus:
$$\nabla.B = 0$$ .......(4)
Equ(4) is the differential form of the Maxwell second equation.

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