${\displaystyle \Phi ={\displaystyle \underset{\text{S}}{\int }B}\cdot e_{\text{n}}\text{d}A}$

where e_ndA is the vector surface element

${\displaystyle \Phi ={\displaystyle \underset{\text{S}}{\int }B}\cdot e_{\text{n}}\text{d}A}$

où e_ndA est l'élément vectoriel de surface