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Question: Answered & Verified by Expert
Consider a current carrying wire (current I) in the shape of a circle.
PhysicsCurrent Electricity
Options:
  • A
    source of emf
  • B
    electric field produced by charges accumulated on the surface of wire
  • C
    the charges just behind a given segment of wire which push them just the right way by repulsion
  • D
    the charges ahead
Solution:
2665 Upvotes Verified Answer
The correct answer is:
electric field produced by charges accumulated on the surface of wire
As we know, electric current per unit area I/A , is called current density $j$ i.e., $j=\frac{I}{A}$ The SI units of the current density are $\mathrm{A} / \mathrm{m}^2$. The current density is also directed along $\mathrm{E}$ and is also a vector and the relationship is
$$
\mathrm{j}=\sigma \mathrm{E}
$$
Current density changes due to electric field produced by charges accumulated on the surface of wire.

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