Contour Integral/Examples/Electromotive Force

Example of Contour Integral
Let $\mathbf E$ be an electromagnetic field acting over a region of space $R$.

Let $\Gamma$ be a closed contour in $R$.

Let $\d \mathbf l$ be a small element of length of $\Gamma$ at a point $P$.

Then the electromotive force in $\Gamma$ is given by the contour integral:
 * $\ds \int_\Gamma \mathbf E \cdot \d \mathbf l$