Physics · Electromagnetic induction: Faraday's law, induced emf and current, Lenz's law, eddy currents, self and mutual inductance

A cylindrical bar magnet is lying along the axis of a circular coil. If the magn

A cylindrical bar magnet is lying along the axis of a circular coil. If the magnet is rotated about the axis of the coil then

  • A. emf will be induced in the coil
  • B. only induced current will be generate in the coil
  • C. no current will be induced in the coil
  • D. both emf and current will be induced in the coil

Step-by-step solution

When the magnet is rotated about the axis of the coil, the magnetic flux through the coil remains constant because the magnetic field lines are symmetric about the axis and rotation does not alter the number of lines passing through the coil. According to Faraday's law, a change in flux is necessary to induce an emf. Since the flux does not change, no emf is induced, and consequently no current flows in the coil. Therefore, option C is correct.
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