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JEE Main 2022 (27 Jul, Shift 2) · Magnetic Flux & Faraday's Law

Magnetic Flux & Faraday's Law question from JEE Main 2022 (27 Jul, Shift 2)

Q57JEE Main 2022 · 27 JUL · SHIFT 2Medium

Magnetic Flux & Faraday's Law

A conducting circular loop is placed in X−YX - Y plane in presence of magnetic field B⃗=(3t3j^+3t2k^)\vec{B} = \left(3t^{3}\hat{j} + 3t^{2}\hat{k}\right) in SI unit. If the radius of the loop is 1 m1\text{ m}, the induced emf in the loop, at time, t=2 st = 2\text{ s} is nπ Vn\pi\text{ V}. The value of nn is ___________.

Numerical answer type. Work it out, then open the answer.

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Answer: 12

  1. Loop in the XY plane: area vector along k^\hat{k}, so only Bz=3t2B_z = 3t^2 gives flux.
  2. ϕ=3t2×π(1)2=3πt2\phi = 3t^2 \times \pi(1)^2 = 3\pi t^2
  3. e=dϕdt=6πt=12πe = \frac{d\phi}{dt} = 6\pi t = 12\pi V at t=2t = 2 s
  4. So n=12n = 12.
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