Question

For a closed surface, which convention must be followed when assigning the area vector?

Options

• The area vector must be tangent to the surface

• The area vector direction is arbitrary for closed surfaces

• The area vector can point either inward or outward

• The area vector is always taken to point outward along the outward normal

Answer 1

For a closed surface, the area vector must always be directed along the outward normal, pointing away from the enclosed volume. This convention is essential for consistent application of Gauss's law and ensuring that flux calculations have a unique, well-defined sign.