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Concepts Of Physics MCQ Edition [Volume 2]PhysicsMagnetic Field due to a Current

A cylindrical conductor carries a steady electric current. Which of the following statements are true?

Options

  1. AAt the conductor's axis, the electric field is zero.
  2. BIn the conductor's vicinity, the electric field is zero.
  3. CAt the conductor's axis, the magnetic field is zero.
  4. DIn the conductor's vicinity, the magnetic field is zero.

Correct answer

C. At the conductor's axis, the magnetic field is zero.

Step-by-step solution

For a steady current I to flow through a cylindrical conductor, an electric field E must exist inside it to drive the charge carriers, given by J = E . Since the current density J is non-zero, the electric field E is non-zero everywhere inside the conductor, including its axis. By the boundary condition for electric fields, the tangential component of the electric field must be continuous across the surface of the conductor. Therefore, an electric field also exists in the vicinity outside the conductor. Using Amper

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