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A long thin magnet of magnetic moment M is bent into a semi-circle. The decrease in the magnetic moment is

Options

  1. A2 M π
  2. Bπ M 2
  3. CM π - 2 π
  4. DM 2 - π 2

Correct answer

C. M π - 2 π

Step-by-step solution

Magnetic length is the minimum distance between the north pole and the south pole, which is decreased in the second case. M ′ = 2 M π , decrease in magnetic moment = M - 2 M π

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