This is my first post here. I have a problem dealing with Electric flux. According to Gauss's Law, to find electric flux we use equation: ψ=∫D dot dA, both D(Electric flux density) and dA(super small area normal to the surface) are vector quantity. Now this is what I confused, how can "dA" be a vector quantity since it's an area. I may misunderstand something. Thank you!