Easy MCQ +4 / -1 PYQ · JEE Mains 2023

An emf of $0.08 \mathrm{~V}$ is induced in a metal rod of length $10 \mathrm{~cm}$ held normal to a uniform magnetic field of $0.4 \mathrm{~T}$, when moves with a velocity of:

  1. A $20 \mathrm{~ms}^{-1}$
  2. B $2 \mathrm{~ms}^{-1}$ Correct answer
  3. C $3.2 \mathrm{~ms}^{-1}$
  4. D $0.5 \mathrm{~ms}^{-1}$

Solution

<p>The emf induced in a rod moving through a magnetic field is given by Faraday&#39;s law of electromagnetic induction, specifically, in the form of motional emf, which states that:</p> <p>$ \text{emf} = B \cdot L \cdot v $</p> <p>where:</p> <ul> <li>(B) is the magnetic field strength,</li> <li>(L) is the length of the rod, and</li> <li>(v) is the velocity of the rod.</li> </ul> <p>In this case, we are given the emf, (B), and (L), and we need to solve for (v). Rearranging the equation gives:</p> <p>$ v = \frac{\text{emf}}{B \cdot L} $</p> <p>Substituting the given values:</p> <p>$ v = \frac{0.08 \, \text{V}}{0.4 \, \text{T} \times0.1 \, \text{m}} = 2 \, \text{m/s} $</p>

About this question

Subject: Physics · Chapter: Electromagnetic Induction · Topic: Faraday's Laws

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