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- PHY102 Physics II © Dr.Cem Özdoğan
- Flow of charge through the cross-section of a conductor at a particular-point is described by current density, J.
- Current density, J, is a vector quantity that has both magnitude and direction.
- Current is uniform across the surface and parallel to dA.
- Magnitude of current density
- Direction of current density
- It has the same direction as the velocity of moving charges if they are positive and the opposite direction if they are negative.
- Current density can be represented by streamlines.
- Current in Section a is equal to current in Section b since charge is conserved. However, the current density changes-it is greater in the narrower conductor; Ja < Jb