So I'm reading Div, Grad, Curl and All That which is my only exposure to Maxwell's equations. The author started with the integral form of Gauss's law (which I get), where the surface integral of the electric field = the enclosed charge (q) divided by epsilon nought. But in deriving the differential form using the divergence theorem, q becomes the volume times the average charge density (p), but in the final equation (of the differential form) is says the divergence of the electric field equals the charge density (not average) divided by epsilon nought.(adsbygoogle = window.adsbygoogle || []).push({});

Getting to my point, what is the meaning of the charge density in the differential form? If it's not an average, it must vary at the different points in the volume you're considering... so I'm not sure what the p means here. If I'm not being clear please let me know and I'll try to explain it better. Thanks

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# Meaning of p in Gauss's law

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