Consider a current carrying wire (current I) in the shape of a circle. Note that as the current progresses along the wire, the direction of `vecJ` (current density) changes in an exact manner, while the current I remains unaffected. The agent that is essentially responsible for isA. source of emfB. electric field produced by charges accumulated on the surface of wireC. the charges just behind a give segment of wire which push them just the right way by repulsionD. the charges ahead

Consider a current carrying wire (current I) in the shape of a circle.

1.	Consider a current carrying wire (current I) in the shape of a circle. Note that as the current progresses along the wire, the direction of `vecJ` (current density) changes in an exact manner, while the current I remains unaffected. The agent that is essentially responsible for isA. source of emfB. electric field produced by charges accumulated on the surface of wireC. the charges just behind a give segment of wire which push them just the right way by repulsionD. the charges ahead
Answer» Current per unit area (taken normal to the current) `(I)/(A)` is called current density and is denoted by j. The SI units of the current density are `(A)/(m^(2))`. The current density is also directed along E and is also a vector and the relation ship is give by (`J=SE`) The j changes due to electric field produced by charges accumulated on the surface of wire.

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