A copper hoop is held ina vertical east-west plane in a uniform magnetic field whose field lines run along the north-south direction. The largest induced emf is produced when the hoop is.
Correct answer: B. Rotated about an east-west axis
- A. Rotated about a north-south axis
- B. Rotated about an east-west axis
- C. Moved rapidly, without rotation toward the east
- D. Moved rapidly, without rotation toward the south
Explanation
When the copper hoop is rotated about an east-west axis, the maximum induced emf is produced. This is because the magnetic field lines are perpendicular to the plane of the hoop, and the rotation of this hoop in this orientation maximizes the rate of change of the magnetic flux passing through the hoop. According to Faraday's law of electromagnetic induction, a greater rate of change of magnetic flux induces a larger emf in the conductor.
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About Faraday's Law
Faraday's law states that an induced electromotive force equals the rate of change of magnetic flux linkage through a circuit. Questions cover changing field, area, angle or motion, the negative sign associated with Lenz's law, and the distinction between induced emf and the current that may flow in a closed circuit.
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