True or false?

$($a$)$ The area vector

A

of a flat, oriented surface is perpendicular to the surface.

TrueFalse$$

$($b$)$

$6$F $$ dAS

$=6$

$$F $$ dAS

$.$

TrueFalse$$

$($c$)$ If

F

is a constant field and S is a cube oriented outward, then

$$F $$ dAS

$=0$

$.$

F

is a constant field and S is a cube oriented outward, then