Gauss law (integral form) (Flux through closed surface = Q_enc/ε₀)

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Flux through closed surface = Q_enc/ε₀

What each symbol means

SymbolWhat it stands for
d\vec{A}Outward area element
Q_{\mathrm{enc}}Net charge enclosed

When to use this

Any closed surface; E is total field (all charges), but only enclosed Q contributes to net flux.