[justify][code][/code]In two dimensions, the [b]flux[/b] of a vector field across a plane curve is defined to be the "flow rate" of the vector field.[br][br]In many cases vector fields involve no motion (e.g. electric fields, magnetic fields), this definition can be very difficult to comprehend at first. A nice context for working with flux in order to understand its definition is by considering the velocity vector of a fluid (so now we do have motion). In two dimensions, the flux of a fluid across a plane curve is given in units of area per unit time. In other words, the flux tells us how much the fluid (volume) passes through a given surface in one second. [/justify]