Practice question · Multiple choice
A flux integral needs a chosen orientation for the surface, while a surface-area integral does not. Why does flux care about the side?
Hints
- Ask what the sign of a flux is telling you physically.
- Water flowing in and water flowing out are not the same event.
Show the answer
B. Because flux measures what passes THROUGH, and in differs from out
Why
Direction is part of the quantity. Gauss’s law depends on it entirely: a net outward flux means enclosed charge, and the sign is the whole content of the statement.
Practise Surface Integrals
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