it is from electrosats

Question

Consider a current carrying wire (current I) in shape of circle. Note that as the current progress

along the wire , the direction j(current density) changes in exact manner, while current I remain

unaffected. The agent that is essentially responsible is :-

• A. Source of EMF
• B. Electric field produced by charge accumulated on the surface of wire
• C. The charges just behind a given behind segment of wire which push them just right way by repulsion.
• D. The charges ahead

Answer 1

Current per unit area (taken normal to the current), I/A, is called current density and correct option is (D)