Why Does j.ds Have Closed Integral on Electromagnetics Equation?

AI Thread Summary
The discussion centers on the use of a closed integral in the j.ds equation related to electromagnetics. It emphasizes that the closed integral represents a surface enclosing a region of space containing charge, reflecting the principle of charge conservation. The continuity equation is referenced, highlighting that changes in charge are driven by current. The closed surface integral of current density is essential for understanding these changes in a defined spatial region. Overall, the closed integral is crucial for accurately representing electromagnetic phenomena.
bhanesh
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Why j.ds has ' closed integral ' on below equation

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I think this is some kind of continuity equation.Its considering a region of space with some charge inside it.Because charge can't be created or destroyed,the only thing which can cause the amount of charge to change is a current and so we should have a surface integral of current density.But because we're interested in a region of space,the surface is the one enclosing that region which is of course closed.
 

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