Get illustration
Share — copy and redistribute the material in any medium or format
Adapt — remix, transform, and build upon the material for any purpose, even commercially.
Sharing and adapting of the illustration is allowed with indication of the link to the illustration.
The first Maxwell equation in integral form:\[ \oint_A \boldsymbol{E} ~\cdot \text{d}\boldsymbol{a} ~=~ \frac{Q}{\varepsilon_0} \]connects the charge \(Q\) trapped within the surface \(A\) with the electric flux \(\oint_A \boldsymbol{E} ~\cdot \text{d}\boldsymbol{a}\) through the surface \(A\). The scalar product \(\boldsymbol{E} ~\cdot \text{d}\boldsymbol{a}\) picks out only the portion of the electric field \(\boldsymbol{E}\) parallel to the \(\text{d}\boldsymbol{a}\) element. All other parts are eliminated in the scalar product.