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A wire of length L carrying a current I is bent into a circle. The magnitude of the magnetic field at the centre of the circle is

Options

  1. Aπμ 0 I L
  2. Bμ 0 I 2 L
  3. C2 πμ 0 I L
  4. Dμ 0 I 2 πL

Correct answer

A. πμ 0 I L

Step-by-step solution

Length L = circumference of circle = 2 πR ⇒    R = L 2 π ∴   Magnetic field at the centre of circular current loop is B = μ 0 I 2 R = μ 0 I 2   L × 2 π B = μ 0 πI L

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