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Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectromagnetic Induction

A circular coil of one turn with a radius of 5.0 cm is rotated about a diameter at a constant angular speed of 80 revolutions per minute. A uniform magnetic field B = 0.010 T exists in a direction perpendicular to the axis of rotation. Determine the average emf induced in the coil over a long period.

Options

  1. A3.3 10⁻⁴ V
  2. B4.2 10⁻⁴ V
  3. CZero
  4. D6.6 10⁻⁴ V

Correct answer

C. Zero

Step-by-step solution

The magnetic flux linked with the coil at any time t is given by = NBA ( t) . The induced emf in the coil is given by Faraday's law of electromagnetic induction: e = - d dt = NBA ( t) The average induced emf over a long period of time (which includes many complete cycles) is the time average of the induced emf. e_ avg = NBA ( t) = NBA ( t) Since the average value of a sinusoidal function over a complete cycle is zero, the average induced emf over a long period is zero.

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