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MHT CET Medical202622 April 2026Morning ShiftPhysicsElectromagnetic InductionActual

A metal rod of length ' l ' rotates about one of its ends in a plane perpendicular to a magnetic field of induction 'B'. If the emf induced between the ends of the rod is 'e', then the number of revolutions made by the rod per second is

Options

  1. Ae B l^2
  2. Bl^2 eB
  3. CB^2 e l
  4. De B ^2 l

Correct answer

A. e B l^2

Step-by-step solution

The induced emf e across the ends of a metal rod of length l rotating with angular velocity in a perpendicular magnetic field B is given by: e = 1 2 B l^2 The angular velocity is related to the frequency f (number of revolutions per second) by: = 2 f Substituting the value of in the expression for emf: e = 1 2 B (2 f) l^2 e = B f l^2 Rearranging for f , we get: f = e B l^2 Answer: e B l^2

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