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Electric Flux |
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The concept of flux is borrowed from flow of water through a surface. The amount of water flowing through a surface depends on the velocity of water, the area of the surface and the orientation of the surface with respect to the direction of velocity of water.
Though an area is generally considered as a scalar, an element of area may be considered to be a vector because |
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It has magnitude (measured in m ). |
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If the area is infinitisimally small, it can be considered to be in a plane. We can then associate a direction with it. |
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For instance, if the area element lies in the x-y plane, it can be considered to be directed along the z-direction. (Conventionally, the direction of the area is taken to be along the outward normal.) |
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In the figure above, the length of the vector  is chosen to represent the area in some convenient unit and its direction is taken to be along the outward normal to the area. |
