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Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectromagnetic Induction

A metallic square frame of edge a is located in a vertical plane. A uniform magnetic field B acts in the space in a direction perpendicular to the plane of the frame. Two boys pull the opposite corners of the square to deform it into a rhombus. They start pulling the corners at t = 0 and displace them at a uniform speed u . Determine the total charge which flows through a side of the frame by the time the square is d

Options

  1. Aa^2 B 2R
  2. B2a^2 B R
  3. Ca^2 B 2 R
  4. Da^2 B R

Correct answer

D. a^2 B R

Step-by-step solution

The initial area of the square frame of edge a is: A_i = a^2 The initial magnetic flux linked with the frame is: _i = B A_i = B a^2 When the opposite corners are pulled and the frame is deformed into a straight line, the area enclosed by the loop becomes zero. Thus, the final area is: A_f = 0 The final magnetic flux linked with the frame is: _f = B A_f = 0 The magnitude of the change in magnetic flux is: = _i - _f = B a^2 According to Faraday's law of electromagnetic induction, the magnitude of the induced emf is:

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