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Re: [Phys-l] Current as Vector



The usual definition of electric current is the rate at which charge crosses an area,
with a sign that depends on the sign of the moving charge considered, and the component
of the velocity in the direction of the normal to the area. (assuming that we are discussing
small plane areas like the cross-section of a wire.)

Like the component of a force, the current is then a scalar quantity associated with a
particular direction.

The problem may arise because we commonly talk about the current at a point in a
circuit, rather than the current though the cross-section of the wire at that point.
Perhaps drawing a little circle around the wire along with the associated normal direction
would help clarify the situation ?