PX275 - D4a - flux of a vector field through a loop

considering a vector field, $\vec{F}$ , describing a volume of rain falling per second, per unit area
taking the dimensions of the rain falling vertically, ie: $\sim - \hat{k}$
to determine how much flux will go through a loop
the total flux through the loop is: $\vec{F} \cdot \hat{n} A$ , where, $\hat{n}$ is the normal vector to the surface area, $A$ , defined by the loop
it will be maximized for $\vec{F} ∥ \hat{n}$ , and minimized (zero) for $\vec{F} ⊥ \hat{n}$