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MHT CET Medical202622 April 2026Morning ShiftPhysicsMagnetic Effects of CurrentActual

A straight wire carrying a current (I) is turned into a circular loop. If the magnitude of magnetic moment associated with it is 'M', then the length of the wire will be

Options

  1. A4 IM
  2. B4 M I
  3. C4 I M
  4. DM 4 I

Correct answer

B. 4 M I

Step-by-step solution

Let the length of the wire be L . When the wire is bent into a circular loop of radius R , its circumference is equal to the length of the wire: 2 R = L R = L 2 The area of the circular loop is: A = R^2 = ( L 2 )^2 = L^2 4 The magnetic moment M of the current-carrying loop is given by: M = IA = I ( L^2 4 ) Rearranging the above equation to solve for L : L^2 = 4 M I L = 4 M I Answer: 4 M I

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